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Zhao L, Tang X, Huang R, Liu Q, Liao L, Hu Y, He K, Zhang X, Guo J, Chen S, Yang S. Acute hypoxia promotes the liver angiogenesis of largemouth bass (Micropterus salmoides) by HIF - Dependent pathway. FISH & SHELLFISH IMMUNOLOGY 2022; 131:264-273. [PMID: 35940542 DOI: 10.1016/j.fsi.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
A 24-h hypoxia exposure experiment was conducted to determine how hypoxia exposure induce liver angiogenesis in largemouth bass. Nitrogen (N2) was pumped into water to exclude dissolved oxygen into 1.2 ± 0.2 mg/L, and liver tissues were sampled during hypoxia exposure of 0 h, 4 h, 8 h, 12 h, 24 h and re-oxygenation for 12 h. Firstly, the results showed that hypoxia exposure promoted the angiogenesis occurrence by immunohistochemical analysis of vascular endothelial growth factor receptor 2 (VEGFR2). Secondly, the concentration of vasodilation factor increased and it's activity was elevated during 8 h exposure, such as nitric oxide (NO) and nitric oxide synthase (NOS) (p < 0.05). Thirdly, hypoxia exposure promoted angiogenesis through up-regulation the expression of matrix metalloproteinase 2 (MMP-2), jagged, protein kinase B (AKT), phosphoinositide-3-kinase (PI3K), mitogen-activated protein kinase (MAPK) at 4 h; contrarily, the expression of inhibiting angiogenesis genes presented up-regulated at 8 h (p < 0.05), such as matrix metalloproteinase inhibitor-2 (TIMP-2), matrix metalloproteinase inhibitor-3 (TIMP-3). Finally, the genes and proteins that regulate angiogenesis presented obvious chronological order. Parts of them promoted the budding and extension of blood vessels were up-regulated during 4 h-8 h (p < 0.05), such as vascular endothelial growth factor a (VEGFA), VEGFR2, monocarboxylic acid transporter 1 (MCT1), CD147, prolyl hydroxylase (PHD), nuclear factor kappa-B (NF-κB); other part of them promoted blood vessel maturation were highly expressed during 12 h-24 h (p < 0.05), such as angiogenin-1 (Ang-1) and angiogenin-2 (Ang-2). In short, acute hypoxia can promote the liver angiogenesis of largemouth bass by HIF - dependent pathway.
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Affiliation(s)
- Liulan Zhao
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Xiaohong Tang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China; Fish Resources and Environment in the Lpper Reaches of the Yangtze River Observation and Research Station of Sichuan Province, Chengdu, Sichuan, 610011, China.
| | - Rui Huang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Qiao Liu
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Lei Liao
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Yifan Hu
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Kuo He
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Xin Zhang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Jiazhong Guo
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Shiyi Chen
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Song Yang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
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Ahn SJ, Ruiz-Uribe NE, Li B, Porter J, Sakadzic S, Schaffer CB. Label-free assessment of hemodynamics in individual cortical brain vessels using third harmonic generation microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:2665-2678. [PMID: 32499951 PMCID: PMC7249811 DOI: 10.1364/boe.385848] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/07/2020] [Accepted: 04/15/2020] [Indexed: 05/04/2023]
Abstract
We show that third harmonic generation (THG) microscopy using a 1-MHz train of 1,300-nm femtosecond duration laser pulses enabled visualization of the structure and quantification of flow speed in the cortical microvascular network of mice to a depth of > 1 mm. Simultaneous three-photon imaging of an intravascular fluorescent tracer enabled us to quantify the cell free layer thickness. Using the label-free imaging capability of THG, we measured flow speed in different types of vessels with and without the presence of an intravascular tracer conjugated to a high molecular weight dextran (2 MDa FITC-dextran, 5% w/v in saline, 100 µl). We found a ∼20% decrease in flow speeds in arterioles and venules due to the dextran-conjugated FITC, which we confirmed with Doppler optical coherence tomography. Capillary flow speeds did not change, although we saw a ∼7% decrease in red blood cell flux with dextran-conjugated FITC injection.
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Affiliation(s)
- Sung Ji Ahn
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA
| | - Nancy E. Ruiz-Uribe
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA
| | - Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Jason Porter
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Sava Sakadzic
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Chris B. Schaffer
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA
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Smith MM, Lucas AR, Hamlin RL, Devor ST. Associations among hemorheological factors and maximal oxygen consumption. Is there a role for blood viscosity in explaining athletic performance? Clin Hemorheol Microcirc 2016; 60:347-62. [PMID: 23514971 DOI: 10.3233/ch-131708] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study examined the relationship between hematocrit, blood viscosity, plasma viscosity, erythrocyte deformability, and fibrinogen concentration during maximal oxygen uptake in aerobically trained (AT) and resistance trained (RT) athletes. Maximal oxygen uptake was assessed using a Bruce graded exercise treadmill test to exhaustion, and blood samples were collected at rest and immediately following exercise using a venous catheter. Viscometric analyses were performed using a cone and plate viscometer at varying shear rates. Hematocrit was measured as the fraction of erythrocytes suspended in plasma following centrifugation. Erythrocyte rigidity was estimated using the Dintenfass index of red blood cell rigidity. Following maximal treadmill exercise, an increase of blood viscosity at varying shear rates (22.50, 45.00, 90.00, and 225.00 s- 1; P < 0.05) was observed in RT athletes only. Plasma viscosity @ 225.00 s- 1 (1.88 ± 0.09 vs. 1.78 ± 0.03 mPa.s; P < 0.05), erythrocyte rigidity (0.52 ± 0.08 vs. 0.40 ± 0.09; P < 0.05), and plasma fibrinogen (434 ± 7 vs. 295 ± 25 mg/dL; P < 0.01) were all significantly greater in RT than AT athletes following maximal exercise. In summary, AT, but not RT, is associated with a hemorheological profile that promotes both oxygen transport and delivery. The results indicate that hematocrit alone should not be the focus of training and ergogenic supplementation to increase aerobic performance.
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Affiliation(s)
- Michael M Smith
- Department of Human Sciences - Kinesiology Program, The Ohio State University, Columbus, OH, USA
| | - Alexander R Lucas
- Department of Human Sciences - Kinesiology Program, The Ohio State University, Columbus, OH, USA
| | - Robert L Hamlin
- College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Steven T Devor
- Department of Human Sciences - Kinesiology Program, The Ohio State University, Columbus, OH, USA
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Ng YC, Fisher LK, Salim V, Kim S, Namgung B. Visualization and Quantification of the Cell-free Layer in Arterioles of the Rat Cremaster Muscle. J Vis Exp 2016. [PMID: 27805612 DOI: 10.3791/54550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The cell-free layer is defined as the parietal plasma layer in the microvessel flow, which is devoid of red blood cells. The measurement of the in vivo cell-free layer width and its spatiotemporal variations can provide a comprehensive understanding of hemodynamics in microcirculation. In this study, we used an intravital microscopic system coupled with a high-speed video camera to quantify the cell-free layer widths in arterioles in vivo. The cremaster muscle of Sprague-Dawley rats was surgically exteriorized to visualize the blood flow. A custom-built imaging script was also developed to automate the image processing and analysis of the cell-free layer width. This approach enables the quantification of spatiotemporal variations more consistently than previous manual measurements. The accuracy of the measurement, however, partly depends on the use of a blue filter and the selection of an appropriate thresholding algorithm. Specifically, we evaluated the contrast and quality of images acquired with and without the use of a blue filter. In addition, we compared five different image histogram-based thresholding algorithms (Otsu, minimum, intermode, iterative selection, and fuzzy entropic thresholding) and illustrated the differences in their determination of the cell-free layer width.
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Affiliation(s)
- Yan Cheng Ng
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore; Department of Biomedical Engineering, National University of Singapore
| | - Liam K Fisher
- Department of Biomedical Engineering, National University of Singapore
| | - Veena Salim
- Department of Biomedical Engineering, National University of Singapore
| | - Sangho Kim
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore; Department of Biomedical Engineering, National University of Singapore; Department of Surgery, National University of Singapore
| | - Bumseok Namgung
- Department of Biomedical Engineering, National University of Singapore;
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Lamarre Y, Hardy-Dessources MD, Romana M, Lalanne-Mistrih ML, Waltz X, Petras M, Doumdo L, Blanchet-Deverly A, Martino J, Tressières B, Maillard F, Tarer V, Etienne-Julan M, Connes P. Relationships between systemic vascular resistance, blood rheology and nitric oxide in children with sickle cell anemia or sickle cell-hemoglobin C disease. Clin Hemorheol Microcirc 2015; 58:307-16. [PMID: 23302597 DOI: 10.3233/ch-121661] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Vascular function has been found to be impaired in patients with sickle cell disease (SCD). The present study investigated the determinants of systemic vascular resistance in two main SCD syndromes in children: sickle cell anemia (SCA) and sickle cell-hemoglobin C disease (SCC). Nitric oxide metabolites (NOx), hematological, hemorheological, and hemodynamical parameters were investigated in 61 children with SCA and 49 children with SCC. While mean arterial pressure was not different between SCA and SCC children, systemic vascular resistance (SVR) was greater in SCC children. Although SVR and blood viscosity (ηb) were not correlated in SCC children, the increase of ηb (+18%) in SCC children compared to SCA children results in a greater mean SVR in this former group. SVR was positively correlated with ηb, hemoglobin (Hb) level and RBC deformability, and negatively with NOx level in SCA children. Multivariate linear regression model showed that both NOx and Hb levels were independently associated with SVR in SCA children. In SCC children, only NOx level was associated with SVR. In conclusion, vascular function of SCC children seems to better cope with higher ηb compared to SCA children. Since the occurrence of vaso-occlusive like complications are less frequent in SCC than in SCA children, this finding suggests a pathophysiological link between the vascular function alteration and these clinical manifestations. In addition, our results suggested that nitric oxide metabolism plays a key role in the regulation of SVR, both in SCA and SCC.
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Affiliation(s)
- Yann Lamarre
- Inserm U665, Pointe-à-Pitre, F-97159 Guadeloupe, Université des Antilles et de la Guyane, Guadeloupe
| | | | - Marc Romana
- Inserm U665, Pointe-à-Pitre, F-97159 Guadeloupe, Université des Antilles et de la Guyane, Guadeloupe
| | - Marie-Laure Lalanne-Mistrih
- Inserm U665, Pointe-à-Pitre, F-97159 Guadeloupe, Université des Antilles et de la Guyane, Guadeloupe CIC-EC 802 Inserm, pôle Guadeloupe, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Xavier Waltz
- Inserm U665, Pointe-à-Pitre, F-97159 Guadeloupe, Université des Antilles et de la Guyane, Guadeloupe
| | - Marie Petras
- Unité Transversale de la Drépanocytose du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France Centre de référence maladies rare pour la drépanocytose aux Antilles-Guyane, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Lydia Doumdo
- Unité Transversale de la Drépanocytose du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France Centre de référence maladies rare pour la drépanocytose aux Antilles-Guyane, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Anne Blanchet-Deverly
- Unité d'explorations cardiovasculaire du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Jean Martino
- Service de cardiologie du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Benoît Tressières
- CIC-EC 802 Inserm, pôle Guadeloupe, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Frederic Maillard
- Unité Transversale de la Drépanocytose du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France Service de Pédiatrie du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France Centre de référence maladies rare pour la drépanocytose aux Antilles-Guyane, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Vanessa Tarer
- Unité Transversale de la Drépanocytose du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France Centre de référence maladies rare pour la drépanocytose aux Antilles-Guyane, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Maryse Etienne-Julan
- Inserm U665, Pointe-à-Pitre, F-97159 Guadeloupe, Université des Antilles et de la Guyane, Guadeloupe Unité Transversale de la Drépanocytose du Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France Centre de référence maladies rare pour la drépanocytose aux Antilles-Guyane, Centre Hospitalier et Universitaire de Pointe-à-Pitre, Pointe-à-Pitre, France
| | - Philippe Connes
- Inserm U665, Pointe-à-Pitre, F-97159 Guadeloupe, Université des Antilles et de la Guyane, Guadeloupe
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Windberger U, Spurny K, Graf A, Thomae H. Hemorheology in experimental research: is it necessary to consider blood fluidity differences in the laboratory rat? Lab Anim 2014; 49:142-52. [PMID: 25318820 DOI: 10.1177/0023677214555783] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study was designed to identify whether blood fluidity differs between commercially available laboratory rat strains. The hemorheological profiles of seven clinically healthy wild-type rat strains were analyzed to determine whether any diversity in blood fluidity might affect the outcome of cardiovascular studies. Study 1: 65 healthy adult rats (Lewis, Long-Evans, Hairless, Wistar and Fisher; mixed gender and comparable ages) were compared. In order to determine the greatest possible difference, the two strains with the greatest hematocrit (HCT) differences were selected for more detailed evaluation. Red blood cell (RBC) deformability (maximum elongation index, shear stress for half-maximal deformation of RBC; both P < 0.0001), and the effect of plasma protein concentration upon plasma viscosity (P < 0.0001) were different between Lewis and Long-Evans strains. Whole blood viscosity - although different at native HCT (P < 0.004) - was unaltered following HCT standardization of samples. Differences in RBC aggregation were statistically significant but these were small and may not be clinically relevant. Study 2: these 65 animals were compared with 21 animals (10-16 weeks old; both sexes) from mutant strains (Dahl SS/JrHsdMcwiCrl, n = 10; ZDF-Lepr(fa)/Crl, n = 11). In both mutant strains, plasma and whole blood viscosity were increased compared with commonly used strains at native and standardized HCT (P < 0.001). Unusually high RBC aggregation values were seen in the ZDF rat strain (P < 0.001). It was concluded that the variability in blood fluidity among clinically healthy adult laboratory rat strains was both statistically and clinically significant. A hemorheological profile should be added to a routine phenotyping process, since both variables can significantly influence study outcomes.
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Affiliation(s)
- Ursula Windberger
- Decentralized Biomedical Facilities, Department of Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Karl Spurny
- Decentralized Biomedical Facilities, Department of Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Alexandra Graf
- Institute for Medical Statistics, Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
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Namgung B, Liang LH, Kim S. Physiological Significance of Cell-Free Layer and Experimental Determination of its Width in Microcirculatory Vessels. VISUALIZATION AND SIMULATION OF COMPLEX FLOWS IN BIOMEDICAL ENGINEERING 2014. [DOI: 10.1007/978-94-007-7769-9_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Abstract
OBJECTIVE Haemoglobin is a potential nitric oxide (NO) scavenger. Haemoglobin is associated with blood viscosity and the red blood cell free layer width of microvessels that impact on shear stress in the microcirculation. We hypothesized that haemoglobin modulates retinal vascular function. METHODS In 139 nondiabetic male patients with haemoglobin levels within the normal range, the vasodilatatory response of retinal capillary blood flow (RCF) to flicker light exposure and the vasoconstrictor response of RCF to infusion of NO synthase inhibitor N-monomethyl-L-arginine (L-NMMA) were assessed. The latter, because of the selective nature of L-NMMA, reflects a parameter of basal NO activity of retinal vasculature. Examinations of retinal parameters were performed noninvasively and in vivo using scanning laser Doppler flowmetry. RESULTS Patients with haemoglobin greater or equal the median revealed reduced increase of RCF to flicker light exposure (2.83 ± 12 vs. 9.52 ± 14 (%), P adjusted = 0.002), and greater decrease of RCF to L-NMMA infusion (-7.35 ± 13 vs. -0.92 ± 14 (%), P adjusted = 0.008), compared with patients with haemoglobin below the median. Haemoglobin was negatively related to the percentage change of RCF to flicker light exposure (r = -0.249, P = 0.004) and to L-NMMA infusion (r = -0.201, P = 0.018). In multiple linear regression analysis haemoglobin was an independent determinant of the percentage change of RCF to flicker light exposure (model 1: ß = -0.278, P = 0.003 and model 2: ß = -0.283, P = 0.002) and to L-NMMA infusion (model 1: ß = -0.256, P = 0.005 and model 2: ß = -0.269, P = 0.004). CONCLUSION Haemoglobin emerged as an independent determinant of vascular function in the human retinal vascular bed.
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An anti-inflammatory sterol decreases obesity-related inflammation-induced insulin resistance and metabolic dysregulation. Mediators Inflamm 2013; 2013:814989. [PMID: 23431246 PMCID: PMC3572652 DOI: 10.1155/2013/814989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 12/18/2012] [Accepted: 12/20/2012] [Indexed: 12/02/2022] Open
Abstract
Obesity-related inflammation-induced insulin resistance and metabolic dysregulation were investigated in retrospective analysis of placebo hematologic and metabolic laboratory data from trials associated with increasing chronic low-grade inflammation and body mass index. Studies included healthy subjects and those with progressive stages of metabolic dysregulation, including type 2 diabetes mellitus with uncontrolled hemoglobin A1c. Intrasubject variances in erythroid and metabolic values increased with metabolic dysregulation. Random effects were demonstrated in treatment-naïve diabetes for erythroid, glucose, and HbA1c fluctuations. The anti-inflammatory insulin sensitizer, HE3286, was tested for its ability to decrease obesity-related inflammation-induced insulin resistance and metabolic dysregulation in diabetes. HE3286 significantly decreased erythroid and metabolic variances and improved 1,5-anhydroglucitol (a surrogate of postprandial glucose) compared to the placebo group. HE3286 HbA1c decrease correlated with weight loss and inversely with baseline monocyte chemoattractant protein-1 (MCP-1) in metformin-treated diabetics. Normalization of HbA1c to the 84-day average hemoglobin revealed that HE3286 HbA1c decrease correlated with high baseline MCP-1 and MCP-1 decrease in treatment-naïve diabetics. HE3286 decreased insulin resistance, increased the frequency of decreased day 84 HbA1c in metformin-treated subjects, and decreased day 112 HbA1c in treatment-naïve diabetics. HE3286 may be useful to restore metabolic homeostasis in type 2 diabetes.
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Sriram K, Tsai AG, Cabrales P, Meng F, Acharya SA, Tartakovsky DM, Intaglietta M. PEG-albumin supraplasma expansion is due to increased vessel wall shear stress induced by blood viscosity shear thinning. Am J Physiol Heart Circ Physiol 2012; 302:H2489-97. [PMID: 22505638 DOI: 10.1152/ajpheart.01090.2011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied the extreme hemodilution to a hematocrit of 11% induced by three plasma expanders: polyethylene glycol (PEG)-conjugated albumin (PEG-Alb), 6% 70-kDa dextran, and 6% 500-kDa dextran. The experimental component of our study relied on microelectrodes and cardiac output to measure both the rheological properties of plasma-expander blood mixtures and nitric oxide (NO) bioavailability in vessel walls. The modeling component consisted of an analysis of the distribution of wall shear stress (WSS) in the microvessels. Our experiments demonstrated that plasma expansion with PEG-Alb caused a state of supraperfusion with cardiac output 40% above baseline, significantly increased NO vessel wall bioavailability, and lowered peripheral vascular resistance. We attributed this behavior to the shear thinning nature of blood and PEG-Alb mixtures. To substantiate this hypothesis, we developed a mathematical model of non-Newtonian blood flow in a vessel. Our model used the Quemada rheological constitutive relationship to express blood viscosity in terms of both hematocrit and shear rate. The model revealed that the net effect of the hemodilution induced by relatively low-viscosity shear thinning PEG-Alb plasma expanders is to reduce overall blood viscosity and to increase the WSS, thus intensifying endothelial NO production. These changes act synergistically, significantly increasing cardiac output and perfusion due to lowered overall peripheral vascular resistance.
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Affiliation(s)
- Krishna Sriram
- Department of Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, California 92093-0412, USA
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Li X, Popel AS, Karniadakis GE. Blood-plasma separation in Y-shaped bifurcating microfluidic channels: a dissipative particle dynamics simulation study. Phys Biol 2012; 9:026010. [PMID: 22476709 PMCID: PMC3419813 DOI: 10.1088/1478-3975/9/2/026010] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The motion of a suspension of red blood cells (RBCs) flowing in a Y-shaped bifurcating microfluidic channel is investigated using a validated low-dimensional RBC model based on dissipative particle dynamics. Specifically, the RBC is represented as a closed torus-like ring of ten colloidal particles, which leads to efficient simulations of blood flow in microcirculation over a wide range of hematocrits. Adaptive no-slip wall boundary conditions were implemented to model hydrodynamic flow within a specific wall structure of diverging three-dimensional microfluidic channels, paying attention to controlling density fluctuations. Plasma skimming and the all-or-nothing phenomenon of RBCs in a bifurcating microfluidic channel have been investigated in our simulations for healthy and diseased blood, including the size of a cell-free layer on the daughter branches. The feed hematocrit level in the parent channel has considerable influence on blood-plasma separation. Compared to the blood-plasma separation efficiencies of healthy RBCs, malaria-infected stiff RBCs (iRBCs) have a tendency to travel into the low flow-rate daughter branch because of their different initial distribution in the parent channel. Our simulation results are consistent with previously published experimental results and theoretical predictions.
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Affiliation(s)
- Xuejin Li
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
| | - Aleksander S. Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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Park SW, Intaglietta M, Tartakovsky DM. Impact of endothelium roughness on blood flow. J Theor Biol 2012; 300:152-60. [PMID: 22300799 DOI: 10.1016/j.jtbi.2012.01.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 12/16/2011] [Accepted: 01/11/2012] [Indexed: 11/19/2022]
Abstract
Cell free layer (CFL), a plasma layer bounded by the red blood cell (RBC) core and the endothelium, plays an important physiological role. Its width affects the effective blood viscosity as well as the scavenging and production of nitric oxide (NO). Measurements of the CFL and its spatio-temporal variability are highly uncertain, exhibiting random fluctuations. Yet traditional models of blood flow and NO scavenging treat the CFL's bounding surfaces as deterministic and smooth. We investigate the effects of the endothelium roughness and uncertain (random) spatial variability on blood flow and the estimates of effective blood viscosity.
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Affiliation(s)
- Sang Woo Park
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
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