Penetration Of Red Blood Cells Research Articles

Abstract 17167: Black Women Have Evidence of Cardiometabolic Risk and Damage to the Microvascular Glycocalyx 1 to 10 Years After Uncomplicated Pregnancy

Introduction: Endothelial glycocalyx (GCX) is a proteoglycan/glycoprotein rich surface layer that regulates vascular health and function and can be damaged in diabetes and cardiovascular disease. Given the excess risk of adverse pregnancy outcomes (APO), chronic hypertension and CVD in Black compared to White women, we considered that microvasculature and glycocalyx may also differ between groups and contribute to adverse clinical outcomes. Objective: The first step was examining the microvasculature in women with no complications in the index pregnancy (from the medical record) and cardiometabolic risk markers. Methods: Sidestream dark-field imaging of the sublingual microcirculation and glycocalyx was used to compare density, median diameter, perfusion (RBC filling %), and penetration of red cells into the glycocalyx of vessel segments of 20-25μm diameter (PBR), in women 1-10 years after the index pregnancy (mean 8 years after index pregnancy). The study included 67 Black women and 167 White women with no complications (preeclampsia, gestation hypertension, preterm delivery, intrauterine growth restriction or gestational diabetes) in the index pregnancy. Health and pregnancy history were obtained by questionnaire at the study visit. Results: Black women had a greater penetration of red blood cells into the glycocalyx of microvascular segments20-25μm (PBR:2.54±0.41 vs White women 2.40±0.43μm, p=0.02). Perfusion in Black women was reduced (70.5±4.2% vs 72±4.8% p=0.003) compared to white women. Associations remain after adjusting for age, BMI, and time to follow-up. Black women were significantly younger (25± 6 vs 30±5 yrs p<0.001) at index delivery and study visit (34±6 vs 38±6yrs p=0.001); they also had higher BMI both pre-pregnancy (28±7 vs 25±6, p=0.007) and at the study visit (32±7 vs 27±7, p<0.001) and higher fasting insulin(17±36 vs 7±9 p=0.002) at the visit compared to White women. Self-reported history of hypertension, diabetes and APO (outside the index pregnancy) was significantly more common among Black at follow-up. Conclusion: Compared to White women, Black women of reproductive age had evidence of more pronounced microvascular changes potentially related to cardiometabolic risk 1-10 years after an uncomplicated index pregnancy.

In silico analysis for factors affecting anti-malarial penetration into red blood cells

BackgroundMalaria is a parasitic disease that produces significant infection in red blood cells. The objective of this study is to investigate the relationships between factors affecting the penetration of currently available anti-malarials into red blood cells.MethodsFifteen anti-malarial drugs listed in the third edition of the World Health Organization malaria treatment guidelines were enrolled in the study. Relationship analysis began with the prioritization of the physicochemical properties of the anti-malarials to create a multivariate linear regression model that correlates the red blood cell penetration.ResultsIt was found that protein binding was significantly correlated with red blood cell penetration, with a negative coefficient. The next step was repeated analysis to find molecular descriptors that influence protein binding. The coefficients of the number of rotating bonds and the number of aliphatic hydrocarbons are negative, as opposed to the positive coefficients of the number of hydrogen bonds and the number of aromatic hydrocarbons. The p-value was less than 0.05.ConclusionsAnti-malarials with a small number of hydrogen bonds and aromatic hydrocarbons, together with a high number of rotatable bonds and aliphatic hydrocarbons, may have a higher tendency to penetrate the red blood cells.

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

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.

Effect of acute hypernatremia induced by hypertonic saline administration on endothelial glycocalyx in rabbits.

The endothelial glycocalyx (EG) is fragile and sensitive to damage such as exposure to hypernatremia. Our aim was to describe the influence of hypernatremia on the EG in sublingual and brain microcirculation in rabbits. Hypernatremia was induced by intravenous administration of 10% NaCl solution. The sublingual and brain microcirculation were evaluated by the Side-stream Dark Field imaging before (T1) and 20 minutes after infusion of 10% saline (T2). Damage to the EG was quantified by automated analysis of Perfused Boundary Region (PBR) indicating the amount of penetration of red blood cells into the EG. Syndecan-1 levels were also measured. Hypernatremia was reached in all 20 animals, the PBR values of the sublingual area raised from 1,98 (0,3) to 2,17 (0,18) μm (p = 0,05). The levels of syndecan-1 (1,23 (0,36); 1,31 (0,33) ng/l, p = 0,3) did not mirror PBR changes. Hypernatremia increased the PBR within the sublingual microcirculation in our animal model, probably due to compression of the EG related to temporary intravascular hypervolemia and changes of the EG charge in RBC instead of direct damaging effect on EG, which has been excluded by rather unchanged levels of syndecan-1.

209. The microvascular endothelial glycocalyx: impaired barrier function in preeclampsia with small gestational age neonates

Introduction The glycocalyx, the endothelial lining of membrane-bound proteoglycans and glycoproteins, serves as a functional barrier between flowing red blood cells (RBC) and the endothelial cell membrane. Recent studies suggest that damage to the glycocalyx, which can be reflected by deeper radial penetration of RBC into the glycocalyx, contributes to microvascular dysfunction. Hypothesis We hypothesized that women with preeclampsia, especially those who deliver a small-for-gestational age neonate (PE + SGA, birthweight Methods We compared 30 women with a normotensive pregnancy (NP) to 30 women with preeclampsia (PE), matched for gestational age at time of analysis and presence/absence of labor. Using sidestream dark field imaging of the sublingual microcirculation, we measured 1) the accessibility of the RBC into the glycocalyx layer (perfused boundary region, PBR), defined as the difference between median and maximal RBC column widths, and 2) the microvascular density (total length of perfused microvessels/mm2 area). In healthy vessels, PBR is relatively small due to limited penetration of RBC into the glycocalyx. Results We observed no significant group differences in microvascular density (229 ± 75 mm/mm2 PE, 247 ± 88 mm/mm2 NP, P = 0.48) or PBR (2.20 ± 0.22 μm PE, 2.14 ± 0.30 μm NP, P = 0.14). However, the subset of women with PE + SGA (n = 12) evidenced a significant reduction in vascular density (205 ± 67 vs 306 ± 71 mm/mm2, P Discussion The increase in RBC encroachment (PBR) into the microvascular glycocalyx in PE + SGA compared to NP indicates a change in glycocalyx structure which may be associated with a reduced vascular protective function of the glycocalyx, possibly contributing to endothelial and microvascular dysfunction. Funded by NIH-NICHD (P01 HD030367, R21 HD083659), and AHA16SFRN27870000.

Increase in perfused boundary region of endothelial glycocalyx is associated with higher prevalence of ischemic heart disease and lesions of microcirculation and vascular wall.

PBR characterizes penetration of red blood cells inside glycocalyx and its thickness can have profound impact on microcirculation and other vascular parameters. The goal of our study was to reliably quantify PBR and assess its potential use as a new marker of cardiovascular pathology. The study included 208 patients (123 men and 85 women from 40 to 65years of age) with various grades of cardiovascular SCORE risk index and IHD. PBR was quantified by sidestream dark field capillaroscopy with green light excitation. Cutaneous microcirculation was evaluated with laser Doppler fluorometry. Elevated PBR values over 2mm were associated with morphological and functional lesions of arterial wall and microcirculation and lowered levels of ApoA1 lipoprotein. Moreover, elevated PBR values were associated with 2.07-fold increase in prevalence of cerebral atherosclerosis (P=.015) and 2.42-fold increase in prevalence of IHD (P=.024). Increase in PBR was associated with elevated systolic blood pressure. Thus, PBR can be considered a new highly reproducible and promising marker candidate for non-invasive diagnostics of IHD and cerebral atherosclerosis suggesting important role of microcirculation in development and progression of cardiovascular diseases.

Dark field microscopy for the endothelial glycocalyx study: first russian experience; the reproducibility of the method

Introduction and purpose. Endothelial glycocalyx is a protective structure of the vascular bed and is damaged in early stages of cardiovascular diseases. Dark field microscopy can determine the depth of penetration of red blood cells in endothelial glycocalyx to estimate the perfusion boundary region (PBR). The aim of this study was to test and validate this method. Materials and methods. The study involved 38 healthy volunteers aged from 28 to 65 years (18 women and 20 men). The sidearm dark field microscopy of the mucosal microvessels in the sublingual area was used to determine the depth of penetration of red blood cells in endothelial glycocalyx to estimate PBR. Results end discussion. The results indicate good tolerability of the test by patients. Our data on the structure of microvessels were highly reproducible and did not depend on the sampling region within sublingual area and on time intervals between sampling. PBR value was not gender-dependent. Conclusion. The dark field microscopy method passed the first step of validation, showing a good feasibility and tolerability, as well as high reproducibility of measurements that are independent of the sampling region and time intervals between sampling.

Biomarkers for hepatic sinusoidal obstruction syndrome after hematopoietic cell transplantation.

Biomarkers for hepatic sinusoidal obstruction syndrome after hematopoietic cell transplantation.

Rapid Insulin-Mediated Increase in Microvascular Glycocalyx Accessibility in Skeletal Muscle May Contribute to Insulin-Mediated Glucose Disposal in Rats

It has been demonstrated that insulin-mediated recruitment of microvascular blood volume is associated with insulin sensitivity. We hypothesize that insulin rapidly stimulates penetration of red blood cells (RBC) and plasma into the glycocalyx and thereby promotes insulin-mediated glucose uptake by increasing intracapillary blood volume. Experiments were performed in rats; the role of the glycocalyx was assessed by enzymatic degradation using a bolus of hyaluronidase. First, the effect of insulin on glycocalyx accessibility was assessed by measuring the depth of penetration of RBCs into the glycocalyx in microvessels of the gastrocnemius muscle with Sidestream Dark-field imaging. Secondly, peripheral insulin sensitivity was determined using intravenous insulin tolerance tests (IVITT). In addition, in a smaller set of experiments, intravital microscopy of capillary hemodynamics in cremaster muscle and histological analysis of the distribution of fluorescently labeled 40 kDa dextrans (D40) in hindlimb muscle was used to evaluate insulin-mediated increases in capillary blood volume. Insulin increased glycocalyx penetration of RBCs by 0.34±0.44 µm (P<0.05) within 10 minutes, and this effect of insulin was greatly impaired in hyaluronidase treated rats. Further, hyaluronidase treated rats showed a 35±25% reduction in whole-body insulin-mediated glucose disposal compared to control rats. Insulin-mediated increases in capillary blood volume were reflected by a rapid increase in capillary tube hematocrit from 21.1±10.1% to 29.0±9.8% (P<0.05), and an increase in D40 intensity in individual capillaries of 134±138% compared to baseline at the end of the IVITT. These effects of insulin were virtually abolished in hyaluronidase treated animals. In conclusion, insulin rapidly increases glycocalyx accessibility for circulating blood in muscle, and this is associated with an increased blood volume in individual capillaries. Hyaluronidase treatment of the glycocalyx abolishes the effects of insulin on capillary blood volume and impairs insulin-mediated glucose disposal.

Acute gastric changes after intracerebral hemorrhage in rats

Severe intracerebral hemorrhage (ICH) produces gastric pathology in about 30% of the patient population, even after the standard treatment of H 2 receptor blockers or proton pump inhibitors. This study was undertaken to establish a rat model of ICH-induced gastric ulcer. Adult male Sprague–Dawley rats (300–350 g) were divided into two hemorrhage groups and a sham control group. ICH was produced either by injection of 100 μl of autologous arterial blood or by injection of 4 μl saline containing 0.6 unit of bacterial collagenase VII into the right basal ganglia. Rats were sacrificed at 24, 48, 72 h, and 7 days after ICH to harvest brains and stomachs. Greater degrees of hemorrhage and brain edema were observed in collagenase-induced ICH. Motor behavior decreased significantly after 24 h in both models. The incidence of acute ulceration with destruction of the forestomach epithelium was extremely low at 8.7% in the collagenase injection model and 4.8% in the blood injection rats. Small, pinpoint hemorrhages (petechiae) were noticed in 38% of rats after blood injection and 22% after collagenase injection, in the glandular portion of the gastric mucosa with penetration of red blood cells and inflammatory cells into the gastric mucosa. Enhanced tumor necrosis factor alpha (TNFα) and cyclooxygenase 2 (COX-2) expressions were observed in gastric tissues after ICH with more intense staining occurring at 24 and 48 h. Due to the low incidence of ulceration, ICH-induced gastric ulceration in rodents may not appropriate for evaluating the potential human risk of gastric ulceration after ICH.

The effects of pentoxifylline on cochlear blood flow in normotensive and spontaneously hypertensive rats

Normotensive and spontaneously hypertensive rats (SHRs) were given arterial infusions of saline and pentoxifylline in doses of 1.5, 2.0, and 3.0 mg/kg/min. Blood pressure decreased in a dose related fashion with increasing doses of pentoxifylline. Cochlear blood flow, measured via laser Doppler flowmeter, increased with infusion of pentoxifylline in members of both rat strains, but to a greater extent in SHRs than in normotensive animals. The mechanism of action appears to be decreased red blood cell rigidity which allows increased penetration of red blood cells into microvessels of the cochlea.

Kinetics of Partitioning and Binding of Digoxin and Its Analogues in the Subcompartments of Blood

The kinetics of digoxin and analogues (metabolites) in the sub-compartments of blood, erythrocytes and plasma, were first order and concentration independent. The rate and extent of red blood cell partitioning of the tested compounds were, according to first-order kinetics, identical in the presence and absence of structurally related compounds and dependent on lipophilicity and temperature; red blood cell penetration was a reversible process. Erythrocyte partitioning of digoxin and its analogues was postulated to be by passive diffusion. There was significant intracellular binding of the compounds, and hemoglobin was the major ligand. The kinetics of red blood cell partitioning of the individual compounds were fitted according to a closed two- or three-compartment model. The latter indicated the existence of two kinetically separable compartments within the red blood cells. Model-independent mean transit times of red blood cell-plasma water partitioning of the compounds depended largely on the lipophilicity and were a thousand times greater for the least lipophilic analogues than for the most lipophilic derivatives. Red blood cell partitioning of digoxin and its metabolites under in vivo and in vitro conditions, were equivalent. Plasma protein binding of the tested compounds was concentration independent, unaltered in the presence of the analogues, and temperature independent between 24°C and 37°C. Binding to albumin in buffer solution was significantly larger than to albumin in plasma for all the compounds. Binding of digoxin and its analogues to albumin in buffer solution increased with increasing lipophilicity of the compounds.

Assay of erythrocyte components as inhibitors of Plasmodium falciparum merozoite invasion of erythrocytes.

Three red blood cell membrane fractions (Band 3, macromolecules exhibiting I antigenic determinants, and a delipidated glycoprotein fraction) were separated from red blood cell membranes and tested for their ability to inhibit penetration of red blood cells by Plasmodium falciparum merozoites in an in vitro inhibition assay. The delipidated glycoprotein fraction (containing the major sialoglycoproteins and devoid of Band 3) was the only fraction that inhibited merozoite invasion. This fraction showed 73% and 70% inhibition at 1 mg/ml and 500 micrograms/ml, respectively, and slight inhibition below these levels.

Acute phalloidin poisoning in dogs.

The acute toxic effects of phalloidin, a toxin from the green deathcup, Amanita phalloides, were tested in dogs. No fatalities occurred following intravenous injection; however, the biochemical parameters GPT, GOT, alkaline phosphatase, and total bilirubin yielded pathological values. Histologically the liver parenchyma revealed hemorrhagic necrosis and peliosis-like changes with penetration of red blood cells into hepatocytes.

Renal, biliary and intestinal clearance of a quaternary ammonium compound, emepronium in the dog.

Abstract Different routes of elimination of emepronium have been quantitated in conscious and anaesthetized dogs. Smoothed plasma concentration time curves and urinary excretion data obtained following intravenous bolus injection of 5 mg/kg indicate at least four different phases with the following half‐lives: 5 min., I hour, 10 hours and 9 days. The initial dilution space, 0.2‐0.6 l/kg, is rather similar to the extracellular volume (0.20‐0.35 l/kg). From infusion experiments plasma clearance of emepronium have been found to be 33±2 ml. min‐1.kg‐1 (meani ± S.E.M., n = 14). The drug is secreted by the renal tubules at a maximum rate of 20 μg/min. at a plasma concentration of about 200 μg/l. Compared with other quaternary ammonium compounds, this is an easily saturated mechanism with a low capacity. The renal clearance constitutes about 30 % of the plasma clearance at a plasma concentration of 200 μg/l. The biliary excretion rate increases proportionally to a plasma concentration up to 100 μg/l and then reaches a maximal rate which is dependent on the bile flow. The biliary clearance decreases from 7 to 2 ml.min.‐1.kg‐1 when the bile flow changes from 7 to 4 g/ hour and the plasma concentration is 200 μg/l. Experiments with bile diversion and saline perfusion of isolated intestinal segments reveal an intestinal route of elimination of both emepronium and metabolites. The bile diversion experiments indicate that about 5‐15% of an intravenous dose is excreted through the gastrointestinal epithelium. Perfusion of isolated intestinal loops indicates an apparent clearance of 4‐5 ml. min‐1.m‐1 over a wide range of steady state plasma concentrations (20‐1200 μ/l). An apparent total intestinal clearance could be calculated to about 7 ml. min.‐1.kg‐1. The remaining part of the plasma clearance (about 8 ml. min.‐1. kg‐1 in an anaesthetized dog) is accounted for by metabolism. The degree of protein binding has been shown to be low, about 20 per cent, and the red blood cell penetration in vitro is only 1‐10% of the total amount present in whole blood.

Influence of Microwave Heat on Bone Discoloration

BONE discoloration in defrosted fryers is objectionable. This dark color causes an unsightly condition of the bones and the adjacent meat of immature chickens. Even though the flavor is not altered by the discoloration many people object to this condition and discriminate against purchasing frozen fryers.Koonz and Ramsbottom (1947) reported that bone discoloration is caused by the penetration of red blood cells through porous bones by the process of freezing and thawing. The hemoglobin collected on the outer surface of the bones is oxidized to the dark colored methemoglobin. They founsd that the methods of killing and period of time between slaughter and freezing had no significant effect on the color of poultry bones. Freezing temperatures did not influence discoloration. However, cooking the poultry from a frozen stated helped to minimize the bone discoloration.Woodroof and Shelor (1948) found that blanching cut-up chicken before freezing prevented bone darkening but …