Minimal shedding of the glycocalyx layer during abdominal hysterectomy

Circulating glycocalyx shedding products as biomarkers for evaluating prognosis of patients with out-of-hospital cardiac arrest after return of spontaneous circulation

The endothelial glycocalyx is damaged in postcardiac arrest syndrome (PCAS), but the prognostic value is unknown. We aimed to observe the expression and prognostic value of glycocalyx shedding products, including syndecan-1 (SDC-1), hyaluronan (HA), and heparan sulfate (HS) in PCAS. Data on clinical and 28-day outcomes of seventy-one consecutive patients with out-of-hospital cardiac arrest (OHCA) after the return of spontaneous circulation (ROSC) were collected. SDC-1, HA, and HS were measured on days 0, 1, and 3 after ROSC. Thirty healthy individuals were controls. Glycocalyx shedding was observed in human umbilical vein endothelial cells (HUVECs) stimulated during hypoxia and reoxygenation in vitro. Within 4 h of ROSC, SDC-1 and HA levels, significantly increased. In the 28-day non-survivors, HA levels showed a gradual upward trend, SDC-1 remained at a high level, and HS levels first increased, then decreased. Kaplan-Meier curves and binary logistic regression analysis showed the prognostic value of SDC-1 levels on days 0, 1, and 3, HA levels on days 1 and 3, and HS levels on day 1. Only HS levels on day 1 showed a prognostic value for 28-day neurological outcomes. SDC-1 and HA levels were positively correlated with the no-flow time. In vitro, HUVECs showed shedding of SDC-1 and HS during a prolonged duration of hypoxia. After ROSC, SDC-1, HA, and HS levels may predict the 28-day survival after PCAS, and HS levels are associated with functional outcomes.

Comparison of the Effects of Sevoflurane and Desflurane on Endothelial Glycocalyx in Patients Undergoing Laparoscopic Hysterectomy: A Randomized, Double-Blind Trial

Objective

Various enzymes, reactive oxygen species, inflammatory conditions, and major surgeries cause endothelial glycocalyx breakdown. Inhalation of anaesthetic agents may have protective effects on the endothelium. This study compared syndecan-1 and heparan sulfate levels to evaluate the effects of sevoflurane and desflurane on the endothelial glycocalyx.

Methods

This prospective randomized, double-blind study included 46 patients undergoing laparoscopic hysterectomy. The participants were allocated into sevoflurane and desflurane groups. Subsequently, blood samples were drawn at three time points: before anaesthesia induction for a baseline value (T0), after pneumoperitoneum (T1), and after extubation (T2). Heparan sulfate and syndecan-1 levels were measured.

Results

There was no statistical difference between the sevoflurane and desflurane groups in terms of heparan sulfate and syndecan-1 levels at any time point. A significant difference was found only in the desflurane group in the intragroup comparisons of the measurements of heparan sulfate levels (χ2=29.826, P < 0.001). Matched pairs of the time points in the desflurane group showed that P=0.036 (Z=-2.099) for T1-T0, P < 0.001 (Z=-3.924) for T2-T0, and P < 0.001 (Z=-4.197) for T2-T1. The change in percentage between T2 and T1 of heparan sulfate in the desflurane group was found to be statistically significant (P=0.034).

Conclusion

The damage caused by surgical stress on the endothelial glycocalyx can be reduced by both desflurane and sevoflurane. The protective effect of desflurane is more prominent than that of sevoflurane.

Mass intraoperative endothelial glycocalyx shedding affects postoperative systemic inflammation response

BACGROUND

Off-pump coronary artery bypass graft (OPCABG) has a high incidence of postoperative systemic inflammation response syndrome (SIRS), and perioperative endothelial glycocalyx layer (EGL) disruption can be one of the predisposing factors. We hypothesized that EGL shedding happened earlier in OPCABG which can influence on postoperative SIRS, and sevoflurane might preserve EGL better than propofol.

METHODS

We randomly allocated 50 patients undergoing OPCABG to receive either sevoflurane-sufentanil or propofol-sufentanil anesthesia. Plasma syndecan-1, heparan sulfate (HS), atrial natriuretic peptide (ANP), IL-6, and cardiac troponin I (cTnI) were measured. Blood samples were collected at 6 timepoints: induction (T1), before grafting (T2), after grafting(T3), surgery done (T4), postoperative day1 (POD1,T5) and POD2 (T6). SIRS criteria and sequential organ failure assessment (SOFA) score were examined.

RESULTS

There were neither differences of syndecan-1, HS, IL-6 nor of SIRS criteria or SOFA score between the sevoflurane and propofol groups. All patients were pooled as a single group for further statistical analyses, plasma syndecan-1 (P < 0.001) and IL-6 (P < 0.001) increased significantly as a function of time; syndecan-1 increasing correlated significantly with the duration of coronary graft anastomosis (r = 0.329, P = 0.026). Syndecan-1(T3) correlated significantly with ANP(T3) (r = 0.0.354, P = 0.016) and IL-6 (T5) (r = 0.570, P < 0.001). The maximum value of IL-6 correlated significantly with SIRS (r = 0.378, P = 0.010), the maximum value of SOFA score (r = 0.399, P = 0.006) and ICU days (r = 0.306, P = 0.039). The maximum value of SOFA score correlated significantly with the occurrence of SIRS (r = 0.568, P < 0.001) and ICU days (r = 0.338, P = 0.022).

CONCLUSIONS

OPCABG intraoperative early EGL shedding caused of grafts anastomosis greatly affected postoperative SIRS and SOFA score, sevoflurane did not clinically preserve EGL better.

TRIAL REGISTRATION

ChiCTR-IOR-17012535. Registered on 01/09/2017.

The effect of pre-operative methylprednisolone on postoperative delirium in elderly patients undergoing gastrointestinal surgery: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Pre-operative administration of methylprednisolone reduced circulating markers of endothelial activation. This randomized, double-blind was to evaluate whether a single pre-operative dose of methylprednisolone reduced the rate of postoperative delirium (POD) in older patients undergoing gastrointestinal surgery, and its association with the shedding of endothelial glycocalyx markers.

METHODS

168 patients, aged 65-80 years and scheduled for laparoscopic gastrointestinal surgery, were randomized to 2 mg·kg -1 methylprednisolone (Group M, n = 84); or equivalent dose of placebo (Group C, n = 84). The primary outcome was the incidence of delirium during the first 5 days after surgery, assessed by the confusion assessment method (CAM). POD severity was rated daily using CAM-Severity (CAM-S). Level of syndecan-1, heparan sulfate, tumor necrosis factor-α(TNF-α), and brain-derived neurotrophic factor (BDNF) were measured at baseline, 1-day, and 3-day after surgery.

RESULTS

Compared with placebo, methylprednisolone greatly reduced the incidence of delirium at 72 h following surgery [9(10.7%) versus 20(23.8%), P =0.03, OR=2.22(95%CI 1.05-4.59)]. No between-group difference was found in the cumulative CAM-S score (P=0.14). The levels of heparan sulfate, syndecan-1, and TNF-α in Group M were lower than that in Group C (P <0.05 and P <0.01), while the level of BDNF in Group M was higher than that in Group C (P <0.01).

CONCLUSIONS

Pre-operative administration of methylprednisolone does not reduce the severity of POD, but may reduce the incidence of delirium after gastrointestinal surgery in elderly patients, which may be related to a reduction in circulating markers of endothelial degradation, followed by the increase of BNDF level.

Human glycocalyx shedding: Systematic review and critical appraisal

BACKGROUND

The number of studies measuring breakdown products of the glycocalyx in plasma has increased rapidly during the past decade. The purpose of the present systematic review was to assess the current knowledge concerning the association between plasma concentrations of glycocalyx components and structural assessment of the endothelium.

METHODS

We performed a literature review of Pubmed to determine which glycocalyx components change in a wide variety of human diseases and conditions. We also searched for evidence of a relationship between plasma concentrations and the thickness of the endothelial glycocalyx layer as obtained by imaging methods.

RESULTS

Out of 3,454 publications, we identified 228 that met our inclusion criteria. The vast majority demonstrate an increase in plasma glycocalyx products. Sepsis and trauma are most frequently studied, and comprise approximately 40 publications. They usually report 3-4-foldt increased levels of glycocalyx degradation products, most commonly of syndecan-1. Surgery shows a variable picture. Cardiac surgery and transplantations are most likely to involve elevations of glycocalyx degradation products. Structural assessment using imaging methods show thinning of the endothelial glycocalyx layer in cardiovascular conditions and during major surgery, but thinning does not always correlate with the plasma concentrations of glycocalyx products. The few structural assessments performed do not currently support that capillary permeability is increased when the plasma levels of glycocalyx fragments in plasma are increased.

CONCLUSIONS

Shedding of glycocalyx components is a ubiquitous process that occurs during both acute and chronic inflammation with no sensitivity or specificity for a specific disease or condition.

Effect of peri-operative crystalloid fluid rate on circulating hyaluronan in healthy dogs: A pilot study

Hypervolemia can damage the endothelial glycocalyx, a key regulator of vascular permeability, coagulation and inflammation. A starting peri-operative crystalloid fluid rate of 5mL/kg/h is recommended for healthy dogs undergoing elective procedures but higher rates continue to be commonly used. This study aimed to determine if a higher starting perioperative fluid rate was associated with a greater increase in plasma concentrations of hyaluronan, a marker correlated with glycocalyx damage, in systemically healthy dogs undergoing elective surgical procedures. Based on a sample size calculation, 38 dogs undergoing ovariohysterectomy or castration were randomly assigned to receive lactated Ringer's at a starting perioperative fluid rate of 10mL/kg/h (n=19) or 5mL/kg/h (n=19). Plasma hyaluronan concentrations were measured by ELISA in pre- and post-fluid therapy samples. There were no significant differences between groups in hyaluronan values before (baseline, P=0.52) or after perioperative fluid administration (P=0.62). Compared to respective baseline values, hyaluronan values significantly increased following 5 and 10ml/kg/h fluid administration (P=0.02 for both comparisons). This preliminary study identified an increase in hyaluronan over the course of fluid therapy with both the low and high fluid rate. One possible explanation is that both fluid rates contribute to glycocalyx disruption, but it should be emphasized that hyaluronan is not specific to the glycocalyx. Further studies are needed to determine the origin of the increased circulating hyaluronan and its clinical significance in dogs undergoing elective surgical procedures.

Evaluation of endothelial glycocalyx in healthy volunteers - An observational study

BACKGROUND

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

A review on the physiological and pathophysiological role of endothelial glycocalyx

The glycocalyx is a gel-like layer covering the luminal surface of vascular endothelial cells. It comprises of membrane-attached proteoglycans, glycosaminoglycan chains, glycoproteins, and adherent plasma proteins. The glycocalyx maintains homeostasis of the vasculature, which includes controlling vascular permeability and microvascular tone, preventing microvascular thrombosis, and regulating leukocyte adhesion. In the past decades, the number of studies on endothelial glycocalyx has steadily grown. Glycocalyx emerged as an essential part of blood vessels involved in multiple physiological functions. Damage to glycocalyx is associated with many types of diseases. The structure and physiology and pathophysiology of the glycocalyx, as well as the clinical effects of glycocalyx degradation, are addressed throughout this study. We strive in particular to define therapeutic approaches for the survival or reparation of the glycocalyx.

Intravenous fluid therapy in the perioperative and critical care setting: Executive summary of the International Fluid Academy (IFA)

Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: resuscitation, replacement, and maintenance. Moreover, the impact of fluid administration as drug diluent or to preserve catheter patency, i.e., fluid creep, should also be considered. As for antibiotics, intravenous fluid administration should follow the four Ds: drug, dosing, duration, de-escalation. Among crystalloids, balanced solutions limit acid–base alterations and chloride load and should be preferred, as this likely prevents renal dysfunction. Among colloids, albumin, the only available natural colloid, may have beneficial effects. The last decade has seen growing interest in the potential harms related to fluid overloading. In the perioperative setting, appropriate fluid management that maintains adequate organ perfusion while limiting fluid administration should represent the standard of care. Protocols including a restrictive continuous fluid administration alongside bolus administration to achieve hemodynamic targets have been proposed. A similar approach should be considered also for critically ill patients, in whom increased endothelial permeability makes this strategy more relevant. Active de-escalation protocols may be necessary in a later phase. The R.O.S.E. conceptual model (Resuscitation, Optimization, Stabilization, Evacuation) summarizes accurately a dynamic approach to fluid therapy, maximizing benefits and minimizing harms. Even in specific categories of critically ill patients, i.e., with trauma or burns, fluid therapy should be carefully applied, considering the importance of their specific aims; maintaining peripheral oxygen delivery, while avoiding the consequences of fluid overload.

Long Intravascular Persistence of 20% Albumin in Postoperative Patients

BACKGROUND

Albumin may persist intravascularly for a shorter time in patients after major surgery than in healthy volunteers due to a surgery-induced breakdown (shedding) of the endothelial glycocalyx layer.

METHODS

In this nonrandomized clinical trial, an IV infusion of 3 mL/kg of 20% albumin was given at a constant rate during 30 minutes to 15 patients on the first day after major open abdominal surgery (mean operating time 5.9 h) and to 15 conscious volunteers. Blood samples and urine were collected during 5 h and mass balance calculations used to estimate the half-lives of the administered albumin molecules and the induced plasma volume expansion, based on measurements of hemodilution and the plasma albumin concentration.

RESULTS

At the end of the infusions, albumin had diluted the plasma volume by 13.3% ± 4.9% (mean ± SD) in the postoperative patients and by 14.2% ± 4.8% in the volunteers (mean difference -0.9, 95% CI, -4.7 to 2.9; 1-way ANOVA P = .61), which amounted to twice the infused volume. The intravascular half-life of the infused albumin molecules was 9.1 (5.7-11.2) h in the surgical patients and 6.0 (5.1-9.0) h in the volunteers (Mann-Whitney U test, P = .26; geometric mean difference 1.2, 95% CI, 0.8-2.0). The half-life of the plasma volume expansion was 10.3 (5.3-17.6; median and interquartile range) h in the surgical patients and 7.6 (3.5-9.0) h in the volunteers (P = .10; geometric mean difference 1.5, 95% CI, 0.8-2.8). All of these parameters correlated positively with the body mass index (correlation coefficients being 0.42-0.47) while age and sex did not affect the results.

CONCLUSIONS

Twenty percent albumin caused a long-lasting plasma volume expansion of similar magnitude in postoperative patients and volunteers.

Hypervolemia does not cause degradation of the endothelial glycocalyx layer during open hysterectomy performed under sevoflurane or propofol anesthesia

BACKGROUND

Fluid-induced hypervolemia may stimulate the release of natriuretic peptides and cause degradation (shedding) of the endothelial glycocalyx layer. Sevoflurane is believed to protect the glycocalyx, but the importance of using sevoflurane to prevent shedding during routine surgery is unclear.

METHODS

The plasma concentrations of brain natriuretic peptide and two biomarkers of glycocalyx shedding, syndecan-1, and heparan sulfate, were measured in 26 patients randomized to receive general anesthesia with sevoflurane or propofol during open abdominal hysterectomy. The fluid therapy consisted of 25 mL/kg (approximately 2 L) of Ringer´s lactate over 30 minutes. Blood hemoglobin and plasma albumin were used to indicate plasma volume expansion and capillary leakage.

RESULTS

The plasma concentrations of brain natriuretic peptide and shedding products showed low levels throughout the surgery (median brain natriuretic peptide, 21 ng/L; syndecan-1, 12.9 ng/mL; and heparan sulfate, 6.5 µg/mL), but the heparan sulfate concentration increased 2 hours post-operatively (to 17.3 µg/mL, P < .005). No differences were noted between the propofol and sevoflurane groups in any of the measured parameters. Albumin was apparently recruited to the bloodstream during the first 20 minutes, when the intravascular retention of infused fluid was almost 100%. The urine flow was <1 mL/min, despite the vigorous volume loading.

CONCLUSIONS

No relevant elevations of brain natriuretic peptide or degradation products of the glycocalyx layer were observed when hypervolemia was induced during open abdominal hysterectomy performed with sevoflurane or propofol anesthesia. Plasma volume expansion from Ringer´s lactate was pronounced.

Efficacy and safety of 20% albumin fluid loading in healthy subjects: a comparison of four resuscitation fluids

Recently, buffered salt solutions and 20% albumin (small volume resuscitation) have been advocated as an alternative fluid for intravenous resuscitation. The relative comparative efficacy and potential adverse effects of these solutions have not been evaluated. In a randomized, double blind, cross-over study of six healthy male subjects we compared the pulmonary and hemodynamic effects of intravenous administration of 30 ml/kg of 0.9% saline, Hartmann's solution and 4% albumin, and 6 ml/kg of 20% albumin (albumin dose equivalent). Lung tests (spirometry, ultrasound, impulse oscillometry, diffusion capacity, and plethysmography), two- to three-dimensional Doppler echocardiography, carotid applanation tonometry, blood gases, serum/urine markers of endothelial, and kidney injury were measured before and after each fluid bolus. Data were analyzed with repeated measures ANOVA with effect of fluid type examined as an interaction. Crystalloids caused lung edema [increase in ultrasound B line ( P = 0.006) and airway resistance ( P = 0.009)], but evidence of lung injury [increased angiopoietin-2 ( P = 0.019)] and glycocalyx injury [increased syndecan ( P = 0.026)] was only observed with 0.9% saline. The colloids caused greater left atrial stretch, decrease in lung volumes, and increase in diffusion capacity than the crystalloids, but without pulmonary edema. Stroke work increased proportionally to increase in preload with all four fluids ( R2 = 0.71). There was a greater increase in cardiac output and stroke volume after colloid administration, associated with a reduction in afterload. Hartmann’s solution did not significantly alter ventricular performance. Markers of kidney injury were not affected by any of the fluids administrated. Bolus administration of 20% albumin is both effective and safe in healthy subjects.

NEW & NOTEWORTHY Bolus administration of 20% albumin is both effective and safe in healthy subjects when compared with other commonly available crystalloids and colloidal solution.

Fluid volume kinetics of 20% albumin

AIMS

A population kinetic model was developed for the body fluid shifts occurring when 20% albumin is given by intravenous infusion. The aim was to study whether its efficacy to expand the plasma volume is impaired after major surgery.

METHODS

An intravenous infusion of 3 mL/kg 20% albumin over 30 minutes was given to 15 volunteers and to 15 patients on the 1^st day after major open abdominal surgery. Blood samples and urine were collected during 5 hours. Mixed-effect modelling software was used to develop a fluid volume kinetic model, using blood haemoglobin and urine excretion the estimate body fluid shifts, to which individual-specific covariates were added in sequence.

RESULTS

The rise in plasma albumin expanded the plasma volume in excess of the infused volume by relocating noncirculating fluid (rate constant k₂₁ ), but it also increased losses of fluid from the kinetic system (k_b ). The balance between k₂₁ and k_b maintained the rise in plasma albumin and plasma volume at a virtual steady-state for almost 2 hours. The rate constant for urinary excretion (k₁₀ ) was slightly reduced by the preceding surgery, by a marked rise in plasma albumin, and by a high preinfusion urinary concentration of creatinine. The arterial pressure, body weight, and plasma concentrations of C-reactive protein and shedding products of the endothelial glycocalyx layer (syndecan-1, heparan sulfate, and hyaluronic acid) did not serve as statistically significant covariates.

CONCLUSIONS

There were no clinically relevant differences in the kinetics of 20% albumin between postoperative patients and volunteers.