Perfused Boundary Region Research Articles

The effects of empagliflozin on arterial stiffness, endothelial function and ventriculoarterial coupling in type 2 diabetes mellitus: 1 year follow up

Abstract Introduction Sodium glucose cotransporters inhibitors (SGLT2i) are currently used in the treatment of patients with type 2 diabetes mellitus (T2DM) who pose high cardiovascular risk. However their effects on arterial stiffness, endothelial function and ventriculoarterial coupling have not been described. Methods We recruited 120 patients with T2DM. They received either the SGLT2i empagliflozin (n=60) or insulin (n=60). We measured at baseline and after 1 year of treatment: 1) Perfused Boundary Region (PBR 5–25μm) to evaluate endothelial glycocalyx integrity via Glycocheck, 2) Pulse wave Velocity (PWVc-f), 3)central systolic blood pressure (cSBP), 4) central Pulse Pressure (cPP) via Complior,5) the ratio PWV/GLS by echocardiography to assess ventriculoarterial coupling (VA coupling). Results The patients were matched for age, gender, smoking, hypertension and hyperlipidemia (p=NS). Hemoglobin A1c was deteriorated in both groups (8.1% vs 8.2%, p=NS). The baseline measurements of aforementioned markers did not differ between the 2 groups (p=NS). PWV was correlated with cSBP (r=0.4.p<0.05) and cPP (r=0.35, p<0.05) for all participants at baseline. After 1 year of treatment both groups achieved significant reduction of HbA1c. Patients treated with insulin showed an increase of PWV in contrary with empagliflogin group (11.4±0.5 to 12.6±0.4 vs 11.7±0.5 to 10.9±0.4, correspondingly, p<0.05). cSBP declined considerably in empagliflozin group (135±10 to 129±10 vs 134±9 to 136±9 respectively, p<0.05) and cPP remained approximately steady (47±8 to 48±8 vs 49±6 to 55±6 respectively, p<0.05) compared with insulin group. PBR dropped in SGLT2i group (2.20±0.2 to 1.98±0.2, p<0.05) whereas PBR fluctuated at the same level in insulin group (2.18±0.2 to 2.15±0.3, p=NS).PWV/GLS fell in both groups but the reduction was more prominent in empagliflozin group (−0.72±0.1 to −0.67±0.1 vs −0.72±0.1 to −0.60±0.1 respectively, p<0.05). Conclusion 1 year treatment with empagliflozin resulted in improved markers of arterial stiffness, ventriculoarterial coupling and endothelial function, independently of glycemic control. Funding Acknowledgement Type of funding source: None

Effects of electronic cigarette on platelet and vascular function after one month of use

Abstract Background and aims Smoking is a major factor that contributes to the development of cardiovascular disease. Smoking cessation delays progress of coronary artery disease. Electronic cigarette is proposed as a bridge to smoking cessation. We examined its effects on platelet function after 1 month of use compared to tobacco smoking. Patients and methods 40 current smokers (mean age 48 years±5) without cardiovascular disease were randomized to smoke either a conventional cigarette (conv-cig) or an electronic cigarette (e-cig) (electronic cigarette fluid with nicotine concentration of 12 mg/dL) for one month. All subjects smoked an electronic cigarette with nicotine concentration 12 mg/dL for one month. Measurements were performed at baseline and after one month of smoking the conventional or electronic cigarette. We measured a) perfused boundary region (PBR) of the sublingual arterial micro vessels (range 5–25 micrometers), a marker inversely related with glycocalyx thickness, b) pulse wave velocity (PWV), central systolic blood pressure (cSBP) and augmentation index (AIx), c) platelet function by two different methods, namely the novel Platelet Function Analyzer PFA-100 and the traditional Light Transmission Aggregometry (LTA) d) the exhaled CO level (parts per million-ppm) as a smoking status marker; and e) the plasma malondialdehyde (MDA) levels, as an oxidative stress burden index. Results After 1 month of electronic smoking, we did not observe any significant change in platelet function and arterial stiffness (p>0.05 for all markers) with the exception of a reduction of MDA (1.22±0.1 vs 1.09±0.1 μmol/L, p=0.03) and exhaled CO; 14.9±0.7 vs 5.9±0.7 ppm, p<0.001. Conversely, after continuation of conventional cigarette smoking for a month, platelet function was further impaired as assessed by PFA [125,5±31,1 vs 152,35±51,4 U, p=0.047) and by LTA (epinephrine as stimulator) [59,8%±16,1 vs 35,6%±19.1, p<0.001] and markers of arterial stiffness were deteriorated, as assessed by PWV (9,5±2,8 vs 10,3±2,9, p=0,028) and by Aixc (8,36±35,9 vs 30,4±21,6, p=0,004). Conclusions Electronic Cigarette smoking has a neutral effect on platelet function and arterial stiffness markers compared to conventional tobacco smoking which further deteriorates platelet and vascular function during one moth of use. Funding Acknowledgement Type of funding source: None

Immediate effects of whole blood donation on the endothelial surface layer and glycocalyx shedding.

The endothelium plays a pivotal role in regulating microvascular function, especially in situations associated with acute blood loss. Whether blood donation and the associated volume loss affects the dimensions of the endothelial surface layer (ESL) and glycocalyx integrity remains unknown. This study was designed to determine real-time ESL and perfusion measurements of the sublingual microcirculation using sidestream dark field imaging performed in healthy subjects shortly before and after a donation of 500 mL whole blood. A novel image acquisition and analysis software (GlycoCheck™) automatically calculated the perfused boundary region (PBR), an inverse parameter for red blood cell (RBC) penetration into the ESL, in vessels between 5 and 25 μm in diameter. Microvascular perfusion was measured by RBC filling percentage. Soluble glycocalyx components were determined in the peripheral circulation. There was no significant immediate effect of whole blood donation on PBR and RBC filling percentage. Linear regression analysis revealed a distinct association between change in PBR and change in RBC filling percentage (regression coefficient β: -0.040; 95% confidence interval: -0.049 to -0.030; p<0.001). A significant reduction in plasma heparan sulphate (1,329±316 vs 1,237±275 ng/mL, p=0.005) and hyaluronan (94±18 vs 90±16 ng/mL, p=0.002) was noted, while syndecan-1 levels (30 [23-50] vs 29 [24-46] ng/mL, p=0.282) remained unchanged. Dimensions and integrity of the ESL appear to remain stable following a 500 mL whole blood donation and reflect its ability to ensure microvascular function and perfusion.

Visual and Biochemical Evidence of Glycocalyx Disruption in Human Dengue Infection, and Association With Plasma Leakage Severity.

Background: Dengue is the most common arboviral infection globally; a minority of patients develop shock due to profound plasma leak through a disrupted endothelial barrier. Understanding of the pathophysiology underlying plasma leak is incomplete, but emerging evidence indicates a key role for degradation of the endothelial glycocalyx.Methods: We conducted an observational study in Vietnam to evaluate the sublingual microcirculation using sidestream darkfield imaging in (1) outpatients with confirmed dengue (2) patients hospitalized with dengue and (3) outpatients with other febrile illness (OFI). We estimated the glycocalyx degradation by measuring the perfused boundary region (PBR hf) and an overall microvascular health score (MVHS) with the software application GlycoCheckTM at enrolment, 48 h later and hospital discharge/defervescence. We measured plasma syndecan1 and endocan at the same time-points. We compared PBR hf, MVHS, syndecan1 and endocan, between (1) outpatients with confirmed dengue vs. OFI and (2) patients with dengue subdivided by clinical severity of plasma leak.Results: We included 75 patients with dengue (41 outpatients, 15 inpatients, 19 in intensive care) and 12 outpatients with OFI. Images from 45 patients were analyzed using GlycoCheckTM. There was no significant difference in PBR hf or MVHS between outpatients with dengue and OFI. Median plasma syndecan1 was not significantly different in outpatients with dengue vs. OFI, while median plasma endocan was significantly lower among patients with dengue vs. OFI during the critical phase. In patients with dengue, PBR hf was higher in patients with Grade 2 vs. Grade 0 plasma leakage during the critical phase (PBR hf 1.96 vs. 1.36 μm for Grade 2 vs. Grade 0 plasma leakage on days 4–6, respectively, p < 0.001). Median levels of plasma syndecan1 and endocan were higher in Grade 2 vs. Grade 0 plasma leakage, especially during the critical phase (Syndecan1 2,613.8 vs. 125.9 ng/ml for Grade 2 vs. Grade 0 plasma leakage on days 4–6, respectively, p < 0.001, and endocan 3.21 vs. 0.16 ng/ml for Grade 2 vs. Grade 0 plasma leakage on days 4–6, respectively).Conclusions: We present the first human in vivo evidence of glycocalyx disruption in dengue, with worse visual glycocalyx damage and higher plasma degradation products associated with more severe plasma leak.

Microvascular dysfunction in COVID-19: the MYSTIC study

RationalePre-clinical and autopsy studies have fueled the hypothesis that a dysregulated vascular endothelium might play a central role in the pathogenesis of ARDS and multi-organ failure in COVID-19.ObjectivesTo comprehensively characterize and quantify microvascular alterations in patients with COVID-19.MethodsHospitalized adult patients with moderate-to-severe or critical COVID-19 (n = 23) were enrolled non-consecutively in this prospective, observational, cross-sectional, multi-center study. Fifteen healthy volunteers served as controls. All participants underwent intravital microscopy by sidestream dark field imaging to quantify vascular density, red blood cell velocity (VRBC), and glycocalyx dimensions (perfused boundary region, PBR) in sublingual microvessels. Circulating levels of endothelial and glycocalyx-associated markers were measured by multiplex proximity extension assay and enzyme-linked immunosorbent assay.Measurements and main resultsCOVID-19 patients showed an up to 90% reduction in vascular density, almost exclusively limited to small capillaries (diameter 4–6 µm), and also significant reductions of VRBC. Especially, patients on mechanical ventilation showed severe glycocalyx damage as indicated by higher PBR values (i.e., thinner glycocalyx) and increased blood levels of shed glycocalyx constituents. Several markers of endothelial dysfunction were increased and correlated with disease severity in COVID-19. PBR (AUC 0.75, p = 0.01), ADAMTS13 (von Willebrand factor-cleaving protease; AUC 0.74, p = 0.02), and vascular endothelial growth factor A (VEGF-A; AUC 0.73, p = 0.04) showed the best discriminatory ability to predict 60-day in-hospital mortality.ConclusionsOur data clearly show severe alterations of the microcirculation and the endothelial glycocalyx in patients with COVID-19. Future therapeutic approaches should consider the importance of systemic vascular involvement in COVID-19.

Evaluation of endothelial glycocalyx in healthy volunteers - An observational study.

Endothelial glycocalyx (EG) is a carbohydrate-rich gel-like mesh covering the apical surface of endothelial cells. It has been linked to the microvascular pathophysiology and tissue metabolism. However, little is known about its condition in young healthy adults. We aimed to describe the condition of EG in young healthy adults by in vivo EG imaging and measurement of syndecan-1, a plasma marker of EG integrity in order to obtain reference values. For in vivo EG studies we used Side-stream Dark Field imaging of the sublingual microcirculation. Recordings were analysed automatically by GlycoCheck software providing the Perfused Boundary Region (PBR) as a marker of EG thickness. Levels of syndecan-1 were analysed in plasma samples by ELISA. 21 volunteers were included in the study. Median of the PBR value was 1.82 μm (interquartile range 1.69-2.01, 95% CI 1.79-1.97). Median concentration of syndecan-1 was 0.3 ng/ml (interquartile range 0.23-0.39, 95% CI 0.27-0.49). This study provides a comparison for cohorts of patients with a particular disease where the EG is presumably damaged. Our findings do not entirely comply with already published data in healthy individuals.

Tocilizumab improves oxidative stress and endothelial glycocalyx: A mechanism that may explain the effects of biological treatment on COVID-19

We investigated the effects of tocilizumab on endothelial glycocalyx, a determinant of vascular permeability, and myocardial function in rheumatoid arthritis (RA). Eighty RA patients were randomized to tocilizumab (n = 40) or conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and glucocorticoids (GC) (n = 40) for 3 months. Forty healthy subjects with similar age and sex served as controls. We measured: (a)perfused boundary region (PBR) of the sublingual arterial microvessels (increased PBR indicates reduced glycocalyx thickness), (b)pulse wave velocity (PWV), (c)global LV longitudinal strain (GLS), (d)global work index (GWI) using speckle tracking echocardiography and e)C-reactive protein (CRP), malondialdehyde (MDA) and protein carbonyls (PCs) as oxidative stress markers at baseline and post-treatment. Compared to controls, RA patients had impaired glycocalyx and myocardial deformation markers (P < 0.05). Compared with baseline, tocilizumab reduced PBR(2.14 ± 0.2 versus 1.97 ± 0.2 μm; P < 0.05) while no significant differences were observed post-csDMARDs + GC(P > 0.05). Compared with csDMARDs + GC, tocilizumab achieved a greater increase of GLS, GWI and reduction of MDA, PCs and CRP(P < 0.05). The percent improvement of glycocalyx thickness (PBR) was associated with the percent decrease of PWV, MDA, PCs and the percent improvement of GLS and GWI(P < 0.05). Tocilizumab improves endothelial function leading to a greater increase of effective myocardial work than csDMARDs + GC through a profound reduction of inflammatory burden and oxidative stress. This mechanism may explain the effects of tocilizumab on COVID-19. Clinical trial registrationurl: https://www.clinicaltrials.gov. Unique identifier: NCT03288584.

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

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.

Effects of Glucagon‐Like Peptide‐1 Receptor Agonists, Sodium‐Glucose Cotransporter‐2 Inhibitors, and Their Combination on Endothelial Glycocalyx, Arterial Function, and Myocardial Work Index in Patients With Type 2 Diabetes Mellitus After 12‐Month Treatment

BackgroundWe investigated the effects of insulin, glucagon‐like peptide‐1 receptor agonists (GLP‐1RA), sodium‐glucose cotransporter‐2 inhibitors (SGLT‐2i), and their combination on vascular and cardiac function of patients with type 2 diabetes mellitus.Methods and ResultsA total of 160 patients with type 2 diabetes mellitus were randomized to insulin (n=40), liraglutide (n=40), empagliflozin (n=40), or their combination (GLP‐1RA+SGLT‐2i) (n=40) as add‐on to metformin. We measured at baseline and 4 and 12 months posttreatment: (a) perfused boundary region of the sublingual arterial microvessels (marker of endothelial glycocalyx thickness), (b) pulse wave velocity (PWV) and central systolic blood pressure, (c) global left ventricular longitudinal, circumferential, and radial strain, (d) myocardial work index (global work index) derived by pressure‐myocardial strain loops using speckle tracking imaging. Twelve months posttreatment, all patients improved perfused boundary region, PWV, global longitudinal strain, global circumferential strain, and global radial strain (P<0.05). GLP‐1RA, SGLT‐2i, and their combination showed a greater reduction of perfused boundary region, PWV, and central systolic blood pressure than insulin, despite a similar glycosylated hemoglobin reduction (P<0.05). GLP‐1RA or GLP‐1RA+SGLT‐2i provided a greater increase of global work index (12.7% and 17.4%) compared with insulin or SGLT‐2i (3.1% and 2%). SGLT‐2i or GLP‐1RA and SGLT‐2i showed a greater decrease of PWV (10.1% and 13%) and central and brachial systolic blood pressure than insulin or GLP‐1RA (PWV, 3.6% and 8.6%) (P<0.05 for all comparisons). The dual therapy showed the greatest effect on measured markers in patients with left ventricular ejection fraction <55% (P<0.05).ConclusionsTwelve‐month treatment with GLP‐1RA, SGLT‐2i, and their combination showed a greater improvement of vascular markers and effective cardiac work than insulin treatment in type 2 diabetes mellitus. The combined therapy as second line was superior to either insulin or GLP‐1RA and SGLT‐2i separately.Registration URL: https://www.clini​caltr​ials.gov. Unique identifier: NCT03878706.

Genesis of Antibiotic Resistance (AR) LXI:Turbulence Modelling: Mechanisms of E‐Complex [Ca2+/Mg2+Ecto‐ATPase (EC 3.6.1.15) /E‐NTPDase (NTPDase1) EC 3.6.1.6) regulated E‐kinase/PKA‐induced E‐NTPase∞CD36/E‐NTPDase∞CD39/CD73 Oligomeric Complex (E complex @ Ec)] activated leucocytes‐platelets‐erythrocytes (LPE) Augment “Hairpin Vortices of Tollmien–Schlichting waves(TSW)” for laminar to turbulent transition

Here we present a plausible pathophysiological cascade initiating the transition of laminar to turbulent flow as a cause for, but not limiting other unknown clinical variable for an increased mortality rate in NCT01663701‐SSSP‐2. Based on the correlation between Perfused Boundary Region (PBR) and number of rolling leukocytes in post‐capillary venules in sepsis cohort, the PBR has been suggested as an index of glycocalyx shedding enhancing the leukocyte–endothelium interaction. NCT00793442 observed that average number of rolling leukocytes was 26 in the sepsis group and 9.8 in the non‐infected control group per field. The sepsis cohort, had an increased number of adhered leukocytes in non‐survivors compared to non‐sepsis cohort. Correlation of aforesaid hemodynamic parameters implicating the LPE impacting the damaged endothelial surface, tissue perfusion and organ dysfunction due to septic shock not withstanding “DIC”. After the LPE start forming in the arterial end of the capillary bed, rolling up and formation of vortex. Amplification of LPE involves the formation of a single vortex of greater strength through the pairing of vortices. As the vortices progress deregulating starling forces from the arterial region in the capillary bed towards the venous end, vortices to become heavily distorted and less distinct. Due to presence of damaged endothelial surface with adhered LPE, flow breaks down, generating a large number of small‐scale eddies, and the flow undergoes rapid transition to the fully turbulent regime. Mixing layers and wakes behind bluff bodies exhibit a sequence of events, leading to transition and turbulent flow. It has known that initial linear instability occurs around Rex, crit = 91 000 forming an unstable two‐dimensional disturbances are called TSW waves. Increased LPE adhesion, endothelial damage, possible scar tissue formation and/or necrotic lesions in the capillary bed are likely to be large enough a secondary, non‐linear, instability mechanism causes the TSW to become three‐dimensional and finally evolve into hairpin Λ‐vortices. In the most common mechanism of transition, would be K‐type transition, where the hairpin vortices are aligned. The hairpin vortices with a high shear region is induced which intensifies, elongates and rolls up. Regions of intense and highly localized changes occur at random times and locations near the damaged endothelial wall. These turbulent spots are carried along with the flow and grow by spreading across the capillary bed, which causes increasing amounts of laminar fluid to take part in the turbulent motion. Under progressive hypotensive state induced endothelial damage and abrupt collapse of interstitial space would result CCP ensuing hypoxia. Such scenario may have been the cause for mortality in NCT01663701‐SSSP‐2.Support or Funding InformationSupported by professional development funds and in part CME activities of Subburaj KannanMD PhD for www.aaets.org

Evidence of Degradation of Endothelial Glycocalyx in African Children with Falciparum Malaria

The microvasculature and endothelium play a pivotal role in pathophysiology of malaria. The endothelial glycocalyx (eGC) is a layer on the luminal side of vascular endothelial cells with involvement in homeostatic functions including regulation of vascular permeability, cellular adhesion and blood flow‐mediated nitric oxide formation. Breakdown products of eGC degradation include glycosaminoglycans (GAG) and syndecan‐1, a core protein. The objective of this study was to evaluate a possible role of eGC breakdown in the pathogenesis of malaria. We prospectively evaluated measures of endothelial glycocalyx integrity in children with severe and moderately severe malaria and healthy controls, and determined the relationship between glycocalyx integrity and markers of malaria severity, microvascular reactivity, and endothelial activation. At the Hubert Kairuki Medical Center in Dar es Salaam, Tanzania we studied 146 subjects, aged 2–11 years, including 60 healthy controls (HC), 49 patients with moderately severe malaria (MSM) and 37 patients meeting WHO criteria for severe malaria (SM). Ethics committee approvals were obtained prior to study initiation. We assessed eGC integrity biochemically by measuring plasma syndecan‐1 (ELISA) and total urinary glycosaminoglycan (GAG) breakdown products (dimethylmethylene blue assay). Angiopoietin‐2 has been reported to cause breakdown of eGC and was measured by ELISA. Quantitative measures of eGC were assessed using non‐invasive, side‐stream dark field (SDF) microscopy of the pinna and axilla. Levels of urinary GAG were increased in malaria patients compared with HC (mean±SEM 4.3±0.4 g/mol creatinine); MSM (12.4±1.0); SM (13.4±1.0); p&lt;0.0001. Plasma levels of angiopoietin‐2 and syndecan‐1 were also elevated in MSM and SM compared with HC (p&lt;0.0001), and significantly correlated with each other. For HC compared with MSM, imaging results showed eGC degradation [an increase in the perfused boundary region (mean±SEM 1.55±0.04 microns vs.1.68±0.05; p&lt;0.05)], increased microvascular density (549± 34 μm/mm2 vs. 649 ±38; p&lt;0.05)], and a decrease in the extent of RBC filling (79.1± 0.98% vs. 74.9±1.02%; p&lt;0.01). In conclusion, these results provide evidence for degradation of the eGC that could contribute to pathogenesis of vascular dysfunction in malaria. Decreased nitric oxide formation, endothelial activation and increased adhesion of infected RBC are potential consequences of the eGC degradation and vascular dysfunction. Administration of an agent that prevents or repairs eGC degradation may be helpful as adjunctive therapy for malaria.Support or Funding InformationNational Institutes of Health (R01 HL130783)

Microvascular Endothelial Glycocalyx Function in Human Pregnancy and Postpartum in Women with a History of Preeclampsia

Preeclampsia (PreE) is a cardiovascular disorder of late pregnancy characterized by de novo hypertension and multi‐organ dysfunction. PreE occurs in 5–8% of all pregnancies and is associated with impaired microvascular endothelial function that promotes progression of the disease. The glycocalyx layer protects the endothelium from leukocyte and platelet adhesion but becomes damaged with aging and cardiovascular disease. However, whether it is altered during healthy pregnancy and/or PreE is unknown. The purpose of this study was to determine 1) the temporal change in glycocalyx across trimesters and postpartum in healthy pregnancy, and 2) whether alterations in glycocalyx layer thickness occurs postpartum in women with a history of PreE. Hematocrit (Hct) and endothelial glycocalyx thickness was assessed by perfused boundary region (PBR5‐25) and red blood cell (RBC) filling percent using Sideview Dark Field imaging (Glycocheck). PBR5‐25 (larger indicates less glycocalyx thickness) and RBC Filling % (lower indicates less vessel RBC perfused) were measured in sublingual microvessels in 1st (n=56), 2nd (n=56), 3rd (n=56) trimester of pregnancy, and 12 weeks postpartum (n=51) in a longitudinal cohort. PBR5‐25 was significantly higher in 2nd and 3rd trimester (2.10 ± 0.03 and 2.12 ± 0.03 uM) compared with the 1st trimester (2.02 ± 0.03 uM, both P&lt;0.05), but was significantly lower 12 weeks postpartum compared with the 2nd and 3rd trimesters (both P&lt;0.001). RBC Filling % was significantly reduced in the 2nd and 3rd trimesters (0.70 ± 0.01 and 0.71 ± 0.01%) compared with the 1st trimester (0.73 ± 0.01%, both P&lt;0.05), but was significantly higher 12 weeks postpartum compared with the 2nd and 3rd trimesters (both P&lt;0.01). Hct was inversely correlated with PBR5‐25 in the 1st, 2nd, 3rd trimesters and 12 weeks postpartum (r= −0.36 to −0.51, all P&lt;0.05). In a separate cross‐sectional cohort at 1–3 years postpartum (n=38), Hct, PBR5‐25 and RBC Filling % were assessed in women with history of PreE (n=19) or healthy pregnancy (n=19). In the cross‐sectional cohort, PRB5‐25 was significantly lower (1.96 ± 0.05 vs. 2.13 ± 0.06 uM, P&lt;0.05) and RBC Filling was significantly higher (0.75 ± 0.01 vs. 0.70 ± 0.01%, P&lt;0.01) among PreE compared with healthy pregnancy. At 1–3 years postpartum, Hct did not differ between groups (P=0.47) and was inversely associated with PBR5‐25 in the healthy controls (r= −0.71, P&lt;0.01) but not PreE (r= 0.12, P=0.64). In conclusion, microvascular endothelial glycocalyx thickness appears to become paradoxically less across trimesters of healthy pregnancy, however volume expansion in normal pregnancy indicated by reduced Hct may have influenced the glycocalyx layer. Glycocalyx thickness appears to be altered postpartum in women with a history of PreE compared with healthy controls, but the mechanisms contributing to differential glycocalyx function postpartum in PreE will require further study.Support or Funding InformationAHA grants 15SFRN23760002 and 18SCG34350001; and University of Iowa ICRU fellowship

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&lt;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.

In Vivo Imaging of the Buccal Mucosa Shows Loss of the Endothelial Glycocalyx and Perivascular Hemorrhages in Pediatric Plasmodium falciparum Malaria.

Severe malaria is mostly caused by Plasmodium falciparum, resulting in considerable, systemic inflammation and pronounced endothelial activation. The endothelium forms an interface between blood and tissue, and vasculopathy has previously been linked with malaria severity. We studied the extent to which the endothelial glycocalyx that normally maintains endothelial function is involved in falciparum malaria pathogenesis by using incident dark-field imaging in the buccal mucosa. This enabled calculation of the perfused boundary region, which indicates to what extent erythrocytes can permeate the endothelial glycocalyx. The perfused boundary region was significantly increased in severe malaria patients and mirrored by an increase of soluble glycocalyx components in plasma. This is suggestive of a substantial endothelial glycocalyx loss. Patients with severe malaria had significantly higher plasma levels of sulfated glycosaminoglycans than patients with uncomplicated malaria, whereas other measured glycocalyx markers were raised to a comparable extent in both groups. In severe malaria, the plasma level of the glycosaminoglycan hyaluronic acid was positively correlated with the perfused boundary region in the buccal cavity. Plasma hyaluronic acid and heparan sulfate were particularly high in severe malaria patients with a low Blantyre coma score, suggesting involvement in its pathogenesis. In vivo imaging also detected perivascular hemorrhages and sequestering late-stage parasites. In line with this, plasma angiopoietin-1 was decreased while angiopoietin-2 was increased, suggesting vascular instability. The density of hemorrhages correlated negatively with plasma levels of angiopoietin-1. Our findings indicate that as with experimental malaria, the loss of endothelial glycocalyx is associated with vascular dysfunction in human malaria and is related to severity.

Non-invasive evaluation of macro- and microhemodynamic changes during induction of general anesthesia - A prospective observational single-blinded trial.

Hypotension and bradycardia are known side effects of general anesthesia, while little is known about further macro- and microhemodynamic changes during induction. Intriguing is furthermore, why some patients require no vasopressor medication to uphold mean arterial pressure, while others need vasopressor support. Determination of macro- and microhemodynamic changes during induction of general anesthesia. We enrolled 150 female adults scheduled for gynaecological surgery into this prospective observational, single-blinded trial. Besides routinely measuring heart rate (HR) and mean arterial blood pressure (MAP), the non-invasive technique of thoracic electrical bioimpedance was applied to measure cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke volume variability (SVV) and index of myocardial contractility (ICON) before induction of anesthesia, 7 times during induction, and, finally, after surgery in the recovery room. Changes in microcirculation were assessed using sidestream dark field imaging to establish the perfused boundary region (PBR), a validated gauge of glycocalyx health. Comparisons were made with Friedman's or Wilcoxon test for paired data, and with Mann-Whitney-U test for unpaired data, with post-hoc corrections for multiple measurements by the Holm-Bonferroni method. 83 patients did not need vasopressor support, whereas 67 patients required therapy (norepinephrine, atropine or cafedrine/theodrenaline) to elevate MAP values to ≥70mmHg during induction, 54 of these receiving norepinephrine (NE) alone. Pre-interventional (basal) values of CO, CI, ICON, SV and SVV were all significantly lower in the group of patients later requiring NE (p < 0.04), whereas HR and MAP were identical for both groups. HR, MAP and CO decreased from baseline to 12 min after induction of general anesthesia in both the patients without and those with NE support. Heart rate decreased significantly by about 25% in both groups (-19 to -21 bpm). The median individual decrease of MAP amounted to -26.7% (19.7/33.3, p < 0.001) and -26.1% (11.6/33.2, p < 0.001), respectively, whereas for CO it was -40.7% (34.1/50.1, p < 0.001) and -43.5% (34.8/48.7). While these relative changes did not differ between the two groups, in absolute values there were significantly greater decreases in CO, CI, SV and ICON in the group requiring NE. Noteably, NE did not restore ICON or the other cardiac parameters to levels approaching those of the group without NE. PBR was measured in a total of 84 patients compiled from both groups, there being no intergroup differences. It increased 6.4% (p < 0.001) from pre-induction to the end of the operation, indicative of damage to microvascular glycocalyx. Non-invasive determination of CO provides additional hemodynamic information during anesthesia, showing that induction results in a significant decrease not only of MAP but also of CO and other cardiac factors at all timepoints compared to baseline values. The decrease of CO was greater than that of MAP and, in contrast to MAP, did not respond to NE. There was also no sign of a positive inotropic effect of NE in this situation. Support of MAP by NE must consequently result from an increase in peripheral arterial resistance, posing a risk for oxygen supply to tissue. In addition, general anesthesia and the operative stimulus lead to an impairment of the microcirculation.

Noninvasive sublingual microvascular imaging reveals sex-specific reduction in glycocalyx barrier properties in patients with coronary artery disease.

BackgroundRisk factors for coronary artery disease (CAD) have been associated with endothelial dysfunction and degradation of the endothelial glycocalyx. This study was designed to compare sublingual microvascular perfusion and glycocalyx barrier properties in CAD patients and controls using noninvasive side stream darkfield imaging.MethodsImaging of the sublingual microvasculature was performed in 52 case subjects (CAD confirmed by left heart catheterization) and 63 controls (low Framingham risk score). Red blood cell (RBC) filling percentage and functional microvascular density, measures of microvascular perfusion, and perfused boundary region (PBR), an index of glycocalyx barrier function, were measured in microvessels with a diameter ranging from 5–25 µm.ResultsRBC filling percentage was lower in patients with CAD compared to controls (p < .001). Functional microvascular density did not differ between groups. The overall PBR was marginally greater in the CAD group compared to the control group (p = .08). PBR did not differ between male CAD cases and controls (p = .17). However, PBR was greater in females with CAD compared with female controls (p = .04), indicating reduced glycocalyx barrier function. This difference became more pronounced after adjusting for potential confounders.ConclusionsOur data suggest that patients with CAD are characterized by a reduction in percentage of time microvessels are occupied by RBCs. In addition, CAD is significantly associated with impaired sublingual microvascular glycocalyx barrier function in women but not men. More research is needed to determine the significance of peripheral microvascular dysfunction in the pathophysiology of CAD, and how this may differ by sex.

414 Ventricular-arterial interaction predicts response to cardiac resynchronization therapy: a link with improvement of endothelial function and arterial elastic properties

Abstract Background Endothelial dysfunction (ED) is a hall mark of chronic heart failure and has been linked to disease progression, hospitalizations and mortality. Purpose to evaluate the impact of cardiac resynchronization therapy (CRT) in ED and to determine predictors of response to CRT Methods CRT recipients from 19/07/2016 until 19/10/2018 were studied at baseline and 3 months after. In each visit we evaluated a 12 lead ECG, carotid to femoral pulse wave velocity (cfPWV), flow-mediated dilatation of the brachial artery (FMD), left ventricle ejection fraction (LVEF) and left ventricle (LV) global longitudinal strain (GLS). We evaluated arterial elastance (Ea) to ventricular elastance (Ees) ratio (Ea/Ees) by echocardiography and the ratio of cfPWV to GLS, as valid markers of ventricular-arterial interaction. We also assessed the layer of endothelial glycocalyx by measurement of Perfused Boundary Region (PBR) of the sublingual microvessel range:5-25 microns. Results 32 patients with a mean age 65.5 (±10.9) years and severe LV systolic dysfunction were enrolled. During follow-up, LVEF, GLS, LVESV and all ED markers exhibited significant improvement (table 1). 23 patients were responders. Among the baseline vascular function markers, only the ratio cfPWV/GLS predicted response to CRT (OR: 0.245, 95%CI: 0.042-0.759, p = 0.044).Threshold analysis showed that the best threshold of cfPWV/GLS for response to CRT was 2.75 (specificity: 0.67%, sensitivity: 0.94%). Conclusions After 3 months of CRT, endothelial function, arterial elasticity and ventricular arterial interaction are improved. The baseline ratio cfPWV/GLS, a novel marker of ventricular arterial interaction, can be applied to predict response to CRT. table 1 Baseline Follow-up Change Measurement mean (sd) mean (sd) mean (sd) p-value SBP (mmHg) 126 (19) 128 (16) 2.18 (11.98) 0,465 DBP (mmHg) 79 (9) 80 (9) 1.06 (8.58) 0,618 LVEF (%) 27 (7) 35 (9) 7.50 (4.77) &amp;lt;0.001 LVESV (mL) 151 (42) 120 (46) -26.91 (17.20) &amp;lt;0.001 GLS (%) 6.47 (2.89) 9.33 (4.18) 2.85 (2.28) &amp;lt;0.001 FMD (%) 5.88 (2.79) 10.25 (3.67) 4.37 (3.34) &amp;lt;0.001 Ea/Ees 2.81 (1.10) 2.04 (0.99) -0.77 (0.47) &amp;lt;0.001 cfPWV 11.11 (2.61) 10.01 (2.45) -1.10 (1.56) 0,003 PBR 5-25(microns) 2.26 (0.20) 2.14 (0.24) -0.13 (0.25) 0,028 cfPWV/GLS 2.18 (1.46) 1.45 (1.11) -0.73 (0.55) &amp;lt;0.001 Measurements at baseline, follow-up and their change during study Abstract 414 Figure. picture 1

P831 Anti-inflammatory treatment improves endothelial glycocalyx, peripheral and coronary microcirculatory function and myocardial deformation in inflammatory bowel disease patients

Abstract Funding Acknowledgements Hellenic Society of IBD study (EOMIFNE) Introduction Inflammatory bowel diseases (IBD) alter gastrointestinal physiology and mucosal immunity through a complex inflammatory process. The extensive inflammation leads to significant arterial endothelial dysfunction as well as modification of cardiac structure and function. This study is performed to test the hypothesis that treatment with TNF-a inhibitor or surgical intervention in the IBD population improves cardiovascular function through anti-inflammatory mechanisms. Methods Thirty-seven IBD patients (28 CD and 9 UC, 39 ± 12 years, 62% male) were examined at baseline and 4 months after pharmaceutical (TNF-a inhibitor) (16 patients) or surgical intervention (21 patients). Subjects with a history of established cardiovascular risk factors were excluded. We measured a) carotid-femoral pulse wave velocity (PWV - Complior SP ALAM), central systolic blood pressure (cSBP) and augmentation index (AI), b) flow mediated dilatation (FMD) of the brachial artery), c) perfused boundary region(PBR) of the sublingual arterial microvessels using Sideview Darkfield imaging, d) LV longitudinal strain (GLS), strain rate (GLSR) and (PWV/GLS) as a marker of ventricular-arterial coupling, e) peak LV twisting, peak twisting velocity (pTwVel) and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography, f) mitral annulus velocities by tissue doppler imaging (S’ and E’) and mitral inflow velocity (E), g) coronary flow reserve (CFR) by Doppler echocardiography, h) C-reactive protein (CRP), white blood cells (WBC). IBD severity was quantified using Mayo score and Harvey-Bradshaw Index (HBI) for UC and CD respectively, and correlated with the cardiovascular disease markers. Results At baseline, the disease severity score was significantly correlated with markers of diastolic dysfunction (lateral mitral E’ velocity r=-0.352, p &amp;lt; 0.05, UntwVelE r = 0.389, p &amp;lt; 0.05), while the WBC values were negatively associated with lateral mitral E’ velocity: r=-0.5, p &amp;lt; 0.05 and CFRvti (r=-0.332, p = 0.05). Four months after anti-inflammatory treatment, there was a reduction of CRP (15.5 ± 4.7 mg/L vs 5.1 ± 2.1 mg/L, p &amp;lt; 0.05) and WBC values (8.6 ± 0.6 vs 6.6 ± 0.7 x 103, p = 0.06). Moreover, post-treatment, there was a significant reduction of central arterial AI (3.58 ± 4.13 vs 0 ± 4.96, p &amp;lt; 0.05), PBR10-19 (2.47 ± 0.09 vs 2.24 ± 0.08 μm, p &amp;lt; 0.05) and PBR5-25 (2.31 ± 0.08 vs 2.14 ± 0.06 μm, p = 0.05) and increase of FMD (7.6%±0.7 vs 12.2%±1.7, p &amp;lt; 0.05), CFR (2.6 ± 0.1 vs 3.2 ± 0.14, p &amp;lt; 0.05), GLS (-18.7 ± 0.46 vs -20 ± 0.49, p &amp;lt; 0.05) and PWV/GLS (-0,48 ± 0.027 vs -0,42 ± 0.028, p &amp;lt; 0.05). No difference in the examined markers was observed between patients treated with anti-TNFa or surgery (p = NS). Conclusion IBD severity is associated with vascular and diastolic dysfunction. Anti-TNFa inhibition treatment or surgical intervention in IBD lead to improved myocardial deformation, endothelial and coronary microcirculatory function possibly through the reduction of excess inflammatory burden.

Erratum: Tie2 Activation Promotes Protection and Reconstitution of the Endothelial Glycocalyx in Human Sepsis

The endothelial glycocalyx (eGC), a carbohydrate-rich layer lining the luminal surface of the endothelium, provides a first vasoprotective barrier against vascular leakage in sepsis. We hypothesized that angiopoietin-2 (Angpt-2), antagonist of the endothelium-stabilizing receptor Tie2, induces a rapid loss of the eGC in human sepsis. Using intravital microscopy, we measured the perfused boundary region (PBR), an inverse parameter of eGC dimensions in sublingual microvessels, in patients with sepsis and age-matched nonseptic subjects. Median PBR values were significantly higher in patients compared with controls and correlated with serum Angpt-2 levels. To transfer and further explore these findings in a cell culture system, we exposed endothelial cells (ECs) to serum (5%) from a subgroup of septic patients and nonseptic controls. Confocal and atomic force microscopy revealed that sepsis serum, but not control serum, induced thinning of the eGC on human ECs in vitro, which correlated with paired PBR values obtained in vivo (r = 0.96, p

Microvascular Alterations During Cardiac Surgery Using a Heparin or Phosphorylcholine-Coated Circuit

Heparin biocompatible coating frequently is used to reduce inflammation and blood coagulation during cardiopulmonary bypass (CPB) in cardiac surgery. Whether heparin coating is protective or damaging to the vascular endothelium is unclear. The authors investigated whether heparin-coated (HC) circuits are associated with better preservation of microcirculatory perfusion and glycocalyx dimensions compared with nonheparin phosphorylcholine-coated (PC) circuits. Prospective, randomized blinded study. Tertiary university hospital. A total of 26 adults undergoing elective coronary artery bypass graft surgery with CPB. PC (n = 13) versus HC circuits (n = 13). Sublingual microcirculatory perfusion was measured before, during, and after CPB using sidestream dark field imaging and analyzed for perfused vessel density and perfused boundary region, an inverse parameter for glycocalyx dimensions. Onset of CPB was associated with an increase in perfused boundary region in the PC group that continued until the third postoperative day (2.0 ± 0.2 to 2.5 ± 0.2 µm; p = 0.018). This was paralleled by increased plasma syndecan-1 levels in the PC group. Contrastingly, both parameters remained unaltered in the HC group compared with baseline levels. CPB decreased perfused vessel density in both groups (CPB v pre-CPB: PC: 17 ± 2 to 13 ± 2 mm/mm2, p = 0.006; HC: 16 ± 2 to 11 ± 2 mm/mm2, p = 0.003) and remained equally altered in the first 3 postoperative days. The use of an HC circuit is associated with better preservation of the endothelial glycocalyx compared with PC circuits, whereas microcirculatory perfusion was disturbed equally in both groups. Hence, CPB-induced microcirculatory perfusion disturbances seem to be coating independent.