Rapid Patient-Side Evaluation of Endothelial Glycocalyx Thickness in Healthy Sedated Cats Using GlycoCheck® Software

The endothelial glycocalyx (EG) determines transvascular fluid fluxes, and influences inflammation, coagulation, and capillary blood flow. The GlycoCheck® software calculates EG thickness using sidestream dark field videomicroscopy recordings. This method has not been evaluated for use in cats. The aim of the present study was to evaluate the use of GlycoCheck® for estimating EG thickness in healthy cats, and to investigate the variability of EG thickness in this population. One hundred and one healthy research-purposed cats were included in the study. The cats were sedated, and a handheld videomicroscope, connected to GlycoCheck® software, was used to evaluate the sublingual microvasculature. The parameters measured included perfused boundary region (PBR, an indirect measurement of EG thickness) in vessels between 5 and 25 μm in diameter, valid vessel density, percentage red blood cell filling, and median red blood cell column width. Heart rate, respiratory rate, pulse oximetry and oscillometric blood pressure readings were also recorded. There were 35 neutered male cats, 11 intact males, 38 neutered females, and 17 intact females. The average age was 63 months (range, 11–160 months). Tolerance intervals for PBR (vessel diameter 5–25 μm) were 1.89–3.00 μm (95% CI, lower limit 1.76–2.04, upper limit 2.83–3.13 μm); for valid vessel density were 73.33–333.33 μm/mm2 (95% CI, lower limit 77.00–99.33, upper limit 312.67–350.33 μm/mm2); for percentage red blood cell filling were 59.85–85.07% (95% CI, lower limit 58.97–63.33, upper limit 83.07–88.20 %); and for median red blood cell column width were 5.63–8.59 μm (95% CI, lower limit 5.28–6.07, upper limit 8.14–9.51 μm). There was a negative association between median red blood cell column width and body weight (p = 0.007). The median red blood cell column was significantly wider in intact females when compared to spayed females (p = 0.033). The GlycoCheck® analysis was easily performed in healthy sedated cats. Clinical variables did not have an effect on the EG thickness. These results suggest that this technique could be valuable for evaluation of the EG and microvascular parameters in cats.

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Nanometer precise red blood cell sizing using a cost-effective quantitative dark field imaging system

Biomedical Optics Express ◽

10.1364/boe.405510 ◽

2020 ◽

Vol 11 (10) ◽

pp. 5950

Author(s):

Xiaoya Chen ◽

Peng Luo ◽

Chuanzhen Hu ◽

Shaojie Yan ◽

Dapeng Lu ◽

...

Keyword(s):

Blood Cell ◽

Red Blood Cell ◽

Imaging System ◽

Cost Effective ◽

Dark Field ◽

Dark Field Imaging ◽

Cell Sizing ◽

Field Imaging

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Abstract MP61: Evidence of Impaired Microvascular Function a Decade After Delivery in Women With Placental Malperfusion Lesions

Circulation ◽

10.1161/circ.141.suppl_1.mp61 ◽

2020 ◽

Vol 141 (Suppl_1) ◽

Author(s):

Alisse Hauspurg ◽

Judith Brands ◽

Robin Gandley ◽

Matthew F Muldoon ◽

William Tony Parks ◽

...

Keyword(s):

Disease Risk ◽

Gestational Hypertension ◽

Boundary Region ◽

Dark Field ◽

Endothelial Glycocalyx ◽

Sidestream Dark Field ◽

Sublingual Microcirculation ◽

Dark Field Imaging ◽

Median Diameter ◽

History Of

Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by incomplete vascular remodeling and vessel features similar to atherosclerosis. MVM lesions indicate a maladaptive maternal vascular response to pregnancy, are often detected in hypertensive disorders of pregnancy (HDP), and may provide a pathologic link to future cardiovascular disease. The endothelial glycocalyx is a glycoprotein-rich layer that is critical for microvascular health and damage may have an important role in the pathophysiology of microcardiovascular disease risk. Hypothesis: We hypothesized that women with malperfusion lesions of the placenta are more likely to evidence microvascular glycocalyx derangement a decade after delivery compared to women without these lesions and that this effect would be most pronounced among women with a history of HDP. Methods: A total of 412 women with placental pathology (N=129 with MVM lesions, N=283 without MVM lesions) were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a blinded perinatal pathologist . HDP (including preeclampsia and gestational hypertension) were abstracted from the medical record. Glycocalyx barrier function was assessed using sublingual sidestream dark field imaging, with reduction defined as deeper penetration of red blood cells (RBCs) into the glycocalyx of the sublingual microcirculation (5-25μm diameter). We compared the median diameter (size) of microvessels, penetration of RBCs into the glycocalyx (perfused boundary region, PBR) and microvascular density (total length of perfused microvessels/mm 2 surface area) in women with and without MVM lesions. Results: Women with placental MVM lesions had smaller-sized sublingual vessels (median 8.59 μM [IQR 8.12, 9.19] vs. 9.01 μM [IQR 8.37, 9.64]; p<0.001), and a lower density of vessels compared to women without lesions. Glycocalyx perfused boundary region was unexpectedly lower in women with MVM lesions (median 2.20 μM [IQR 2.06, 2.43] vs. 2.32 μM [IQR 2.15, 2.50]; p=0.003) in 10-19 μM vessels. Women with HDP and MVM lesions appear to be the most impacted, with the smallest size vessels (median 8.47 [IQR 8.09-9.13]) and the lowest glycocalyx PBR across all vessel sizes. Women with MVM lesions without a HDP similarly had evidence of microvascular glycocalyx derangement whereas women with HDP without placental lesions had a glycocalyx profile similar to women without MVM or a history of HDP. Conclusions: A decade after delivery, women with a history of placental malperfusion lesions had alterations in microvascular perfusion. Women with MVM lesions and a history of HDP appear to be the most severely impacted, which may reflect an underlying maladaptive vascular phenotype detected in the placenta at the time of pregnancy that might provide pathologic insight into future maternal microvascular health.

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Effects of high-intensity interval training on microvascular glycocalyx and associated microRNAs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00751.2018 ◽

2019 ◽

Vol 316 (6) ◽

pp. H1538-H1551 ◽

Cited By ~ 3

Author(s):

Boris Schmitz ◽

Hannah Niehues ◽

Malte Lenders ◽

Lothar Thorwesten ◽

Andreas Klose ◽

...

Keyword(s):

High Intensity ◽

Interval Training ◽

Dark Field ◽

Endothelial Glycocalyx ◽

High Intensity Interval Training ◽

Sidestream Dark Field ◽

Sidestream Dark Field Imaging ◽

High Intensity Interval ◽

Glycocalyx Thickness

High-intensity interval training (HIIT) has been proposed to exert vasculoprotective effects. This study aimed to evaluate whether HIIT affects the microvasculature, including the endothelial glycocalyx barrier, and to identify associated microRNAs (miRNAs). Fifty healthy participants (23.1 ± 3.0 yr) performed a 4-wk 4 × 30-s all-out running HIIT. Sidestream dark-field imaging was performed at baseline and follow-up to detect changes of the sublingual microvasculature including the endothelial glycocalyx. Exercise parameters were determined by continuous running field test and documentation of high-intensity runs. miRNAs potentially associated with glycocalyx thickness were selected by structured literature search and blood samples for miRNA, and lactate measurements were drawn at baseline and follow-up HIIT. At baseline, a correlation between maximal exercise performance capacity and glycocalyx thickness (determined by perfused boundary region) was detected ( P = 0.045, r = 0.303). Increased exercise performance at follow-up also correlated with glycocalyx thickness ( P = 0.031, r = 0.416), and increased high-intensity sprinting speed was associated with an increased number of perfused vessels ( P = 0.0129, r = 0.449). Literature search identified miR-143, -96-5p, and -24, which were upregulated by HIIT already at baseline and showed an association with peak blood lactate levels after sprints (all P < 0.05). Moreover, increased baseline miR-143 levels predicted increased glycocalyx thickness at follow-up (AUCmiR-143 = 0.92, 95% confidence interval, 0.81–1.0, P = 0.0008). Elevated resting miR-126 levels after the intervention were associated with cell-free versican mRNA levels. We conclude that HIIT induces changes in the endothelial glycocalyx of the microvasculature. Associated miRNAs such as miR-143 may represent a tool for monitoring early vasculoprotective adaptations to physical activity. NEW & NOTEWORTHY High-intensity interval training is known to improve health-related fitness in general and in lifestyle-induced chronic diseases. To visualize microvasculature structure and to detect exercise-induced changes, sublingual sidestream dark-field imaging microscopy was used, and circulating miRNAs were measured. This study shows that exercise-induced changes correlate with associated circulating miRNA, which might be useful for monitoring vasculoprotective effects. Furthermore, sidestream dark-field imaging may represent a sensitive tool for the early detection of exercise-induced systemic vascular changes.

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Decreased endothelial glycocalyx thickness is an early predictor of mortality in sepsis

Anaesthesia and Intensive Care ◽

10.1177/0310057x20916471 ◽

2020 ◽

Vol 48 (3) ◽

pp. 221-228

Author(s):

Daniëlle MH Beurskens ◽

Martine E Bol ◽

Tammo Delhaas ◽

Marcel CG van de Poll ◽

Chris PM Reutelingsperger ◽

...

Keyword(s):

Organ Failure ◽

Early Stage ◽

Characteristic Curve ◽

Area Under The Curve ◽

Dark Field ◽

Endothelial Glycocalyx ◽

Pathophysiological Mechanism ◽

Heparin Binding ◽

Sidestream Dark Field ◽

Glycocalyx Thickness

Microcirculatory alterations play an important role in the early phase of sepsis. Shedding of the endothelial glycocalyx is regarded as a central pathophysiological mechanism causing microvascular dysfunction, contributing to multiple organ failure and death in sepsis. The objective of this study was to investigate whether endothelial glycocalyx thickness at an early stage in septic patients relates to clinical outcome. We measured the perfused boundary region (PBR), which is inversely proportional to glycocalyx thickness, of sublingual microvessels (5–25 µm) using sidestream dark field imaging. The PBR in 21 patients with sepsis was measured within 24 h of admission to the intensive care unit (ICU). In addition, we determined plasma markers of microcirculatory dysfunction and studied their correlation with PBR and mortality. Endothelial glycocalyx thickness in sepsis was significantly lower for non-survivors as compared with survivors, indicated by a higher PBR of 1.97 [1.85, 2.19]µm compared with 1.76 [1.59, 1.97] µm, P=0.03. Admission PBR was associated with hospital mortality with an area under the curve of 0.778 based on the receiver operating characteristic curve. Furthermore, PBR correlated positively with angiopoietin-2 (rho=0.532, P=0.03), indicative of impaired barrier function. PBR did not correlate with Acute Physiology and Chronic Health Evaluation IV (APACHE IV), Sequential Organ Failure Assessment score (SOFA score), lactate, syndecan-1, angiopoietin-1 or heparin-binding protein. An increased PBR within the first 24 h after ICU admission is associated with mortality in sepsis. Further research should be aimed at the pathophysiological importance of glycocalyx shedding in the development of multi-organ failure and at therapies attempting to preserve glycocalyx integrity.

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New insights into antiphospholipid-related endothelial dysfunction by assessment of vascular glycocalyx layer: results from a preliminary cross-sectional study

Lupus ◽

10.1177/0961203319897958 ◽

2020 ◽

Vol 29 (2) ◽

pp. 157-164 ◽

Cited By ~ 3

Author(s):

S Miranda ◽

P Billoir ◽

M Le Besnerais ◽

R Joannides ◽

V Richard ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Plasma Level ◽

Thiobarbituric Acid ◽

Intima Media Thickness ◽

Carotid Intima Media Thickness ◽

Dark Field ◽

Endothelial Glycocalyx ◽

Sidestream Dark Field ◽

Cross Sectional ◽

Early Atherosclerosis

Introduction Antiphospholipid syndrome (APS) is associated with greater atherothrombotic risk and endothelial dysfunction, suggesting that endothelial glycocalyx is impaired in this disease. Objectives The aim was to investigate the endothelial glycocalyx and the relationship between glycocalyx markers, endothelial dysfunction parameters and atherosclerotic markers in APS. Methods A total of 15 primary arterial APS patients and healthy controls were included in the study. Glycocalyx was assessed in both groups by sublingual sidestream dark field imaging and syndecan-1 plasma level. Endothelial function was evaluated by brachial artery flow-mediated dilatation (FMD) and early atherosclerosis by carotid intima media thickness (IMT). Thrombotic profile was also performed by measuring the plasma level of the tissue factor (TF). Results APS patients had significantly increased syndecan-1 plasma level 38.6 ± 5.0 pg/ml vs. 19.1 ± 3.5 pg/ml; p < 0.01 and a reduced glycocalyx thickness 0.26 ± 0.03 µm vs. 0.75 ± 0.07 µm; p < 0.01 compared with control. FMD was impaired in APS patients compared with control, 5.68% ± 0.42 vs. 8.29 ± 0.30, p < 0.01, respectively. IMT was significantly increased in APS patients compared with control, 0.52 ± 0.13 mm vs. 0.40 ± 0.06 mm, p < 0.01, respectively. Soluble TF, thiobarbituric acid-reactive substances levels were increased in the sera from APS patients compared with control. Conclusions This preliminary study supports, for the first time, that in APS patients endothelial glycocalyx is impaired, which could lead to thrombosis, endothelial dysfunction and early atherosclerosis.

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Exposure to acute normobaric hypoxia results in adaptions of both the macro- and microcirculatory system

Scientific Reports ◽

10.1038/s41598-020-77724-5 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Moritz Mirna ◽

Nana-Yaw Bimpong-Buta ◽

Fabian Hoffmann ◽

Thaer Abusamrah ◽

Thorben Knost ◽

...

Keyword(s):

Cardiac Output ◽

Acute Hypoxia ◽

Capillary Density ◽

Dark Field ◽

Normobaric Hypoxia ◽

Vessel Density ◽

Resistance Arteries ◽

Compensatory Mechanisms ◽

Sidestream Dark Field ◽

Sublingual Microcirculation

AbstractAlthough acute hypoxia is of utmost pathophysiologic relevance in health and disease, studies on its effects on both the macro- and microcirculation are scarce. Herein, we provide a comprehensive analysis of the effects of acute normobaric hypoxia on human macro- and microcirculation. 20 healthy participants were enrolled in this study. Hypoxia was induced in a normobaric hypoxia chamber by decreasing the partial pressure of oxygen in inhaled air stepwisely (pO2; 21.25 kPa (0 k), 16.42 kPa (2 k), 12.63 kPa (4 k) and 9.64 kPa (6 k)). Macrocirculatory effects were assessed by cardiac output measurements, microcirculatory changes were investigated by sidestream dark-field imaging in the sublingual capillary bed and videocapillaroscopy at the nailfold. Exposure to hypoxia resulted in a decrease of systemic vascular resistance (p < 0.0001) and diastolic blood pressure (p = 0.014). Concomitantly, we observed an increase in heart rate (p < 0.0001) and an increase of cardiac output (p < 0.0001). In the sublingual microcirculation, exposure to hypoxia resulted in an increase of total vessel density, proportion of perfused vessels and perfused vessel density. Furthermore, we observed an increase in peripheral capillary density. Exposure to acute hypoxia results in vasodilatation of resistance arteries, as well as recruitment of microvessels of the central and peripheral microcirculation. The observed macro- and microcirculatory effects are most likely a result from compensatory mechanisms to ensure adequate tissue oxygenation.

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In Situ Assessment of the Brain Microcirculation in Mechanically-Ventilated Rabbits Using Sidestream Dark-Field (SDF) Imaging

Physiological Research ◽

10.33549/physiolres.931937 ◽

2011 ◽

pp. 75-81 ◽

Cited By ~ 6

Author(s):

M. ŠITINA ◽

Z. TUREK ◽

R. PAŘÍZKOVÁ ◽

V. ČERNÝ

Keyword(s):

Dark Field ◽

Vessel Density ◽

Flow Index ◽

Target Tissue ◽

Cerebral Microcirculation ◽

Sidestream Dark Field ◽

Mechanically Ventilated ◽

Sdf Imaging ◽

The Brain

Assessment of the cerebral microcirculation by on-line visualization has been impossible for a long time. Sidestream dark-field (SDF) imaging is a relatively new method allowing direct visualization of cerebral surface layer microcirculation using hand-held probe for direct contact with target tissue. The aim of this study was to elucidate the feasibility of studying the cerebral microcirculation in situ by SDF imaging and to assess the basic cerebral microcirculatory parameters in mechanically ventilated rabbits. Images were obtained using SDF imaging from the surface of the brain via craniotomy. Clear high contrast SDF images were successfully obtained. Total small-vessel density was 14.6±1.8 mm/mm2, total all-vessel density was 17.9±1.7 mm/mm2, DeBacker score was 12.0±1.6 mm-1 and microvascular flow index was 3.0±0.0. This method seems to be applicable in animal studies with possibility to use SDF imaging also intraoperatively, providing unique opportunity to study cerebral microcirculation during various experimental and clinical settings.

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VS03.01: QUANTITATIVE IMAGING OF CHANGE IN MICROCIRCULATION BY SIDESTREAM DARK FIELD MICROSCOPY (SDF) AFTER ESOPHAGECTOMY

Diseases of the Esophagus ◽

10.1093/dote/doy089.vs03.01 ◽

2018 ◽

Vol 31 (Supplement_1) ◽

pp. 47-48

Author(s):

Sanne Jansen ◽

Daniel De Bruin ◽

Mark I Van Berge Henegouwen ◽

Ton Van Leeuwen ◽

Suzanne Gisbertz

Keyword(s):

Anastomotic Leakage ◽

Gastric Tube ◽

Average Velocity ◽

Venous Return ◽

Conflicts Of Interest ◽

Dark Field ◽

Vessel Density ◽

Flow Index ◽

High Morbidity ◽

Sidestream Dark Field

Abstract Description Anastomotic leakage is one of the most severe complications after esophageal resection with gastric tube reconstruction. Impaired perfusion of the gastric fundus is seen as the main contributing factor for this complication. Transection of the left gastric and gastro-epiploic artery and veins results in compromised perfusion in the fundus area which can result in anastomotic dehiscence (5–20%), relating to high morbidity and mortality (3–4%). The main objective of this observational study is to evaluation gastric tube microcirculation with Sidestream Darkfield Microscopy (SDF). Method This study included 22 patients (October 2015 - June 2016). Intra-operative microscopic images of gastric tube microcirculation were obtained with SDF directly after reconstruction. Using software (AVA2.0), the following parameters were evaluated: average velocity (μm/sec), Microvascular Flow Index (MFI), Total Vessel Density (TVD), Perfusion Vessel Density (PVD), Proportion of Perfused Vessels (PPV) and the De Backer Score (DBS), to assess change in perfusion. Results SDF accurately visualized and evaluated microcirculation in all patients. A SDF-stabilizer was used to create stable images. The average velocity decreased significantly towards the fundus (P = 0.001). Also, MFI, PVD and PPV were significantly lower towards the fundus, compared to the base of the gastric tube (P = 0.0002). No differences in TVD and DBS were observed, which was associated to the observed vessel dilation in the fundus-area. This vessel dilation proposes that compromised venous return may play an important role in the development of necrosis and leakage. Three patients developed anastomotic leakage. Conclusion This is the first study presenting quantitative microcirculation imaging with SDF of the gastric tube. Velocity, MFI, TVD and PPV were accurate parameters to observe change in perfusion after reconstruction. Also, vessel dilation in the fundus suggests a role for venous return in the development of ischemia. Quantitative microcirculation with SDF could allow for intra-operative early risk stratification, and, potentially, can result in a reduction of anastomotic leakage. Disclosure All authors have declared no conflicts of interest.

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Erythrocyte margination and sedimentation in skeletal muscle venules

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.281.2.h951 ◽

2001 ◽

Vol 281 (2) ◽

pp. H951-H958 ◽

Cited By ~ 20

Author(s):

Jeffrey J. Bishop ◽

Patricia R. Nance ◽

Aleksander S. Popel ◽

Marcos Intaglietta ◽

Paul C. Johnson

Keyword(s):

Skeletal Muscle ◽

Arterial Pressure ◽

Blood Cell ◽

Red Blood Cell ◽

Plasma Layer ◽

Cell Aggregation ◽

Cell Column ◽

Red Blood Cell Aggregation ◽

Blood Cell Aggregation

Previous studies in skeletal muscle of the dog and cat have shown that venous vascular resistance changes inversely with blood flow and may be due mainly to red blood cell aggregation, a phenomenon present in these species. To determine whether red blood cell axial migration and sedimentation contribute to this effect, we viewed either vertically or horizontally oriented venules of the rat spinotrapezius muscle with a horizontally oriented microscope during acute arterial pressure reduction. With normal (nonaggregating) rat blood, reduction of arterial pressure did not significantly change the relative diameter of the red blood cell column with respect to the venular wall. After induction of red blood cell aggregation in the rat by infusion of Dextran 500, red blood cell column diameter decreased up to 35% at low pseudoshear rates (below ∼5 s−1); the magnitude was independent of venular orientation. In vertically oriented venules, the plasma layer was symmetrical, whereas in horizontally oriented venules, the plasma layer formed near the upper wall. We conclude that, although red blood cell axial migration and sedimentation develop in vivo, they occur only for larger flow reductions than are needed to elicit changes in venous resistance.

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