Perioperative implication of the endothelial glycocalyx

Changes of the serum properties and its effect on the endothelial cells restoration in patients with chronic venous disease treated with sulodexide

OBJECTIVE

Inflammation and endothelial dysfunction are important venous changes in patients with chronic venous disease (CVD). The use of the venoactive drugs remains an important treatment modality for patients with CVD, reducing the severity of the CVD-related symptoms and swelling but also reducing inflammation and protecting endothelial cells. In this research, the effects of the serum obtained from patients with CVD before and after sulodexide treatment were evaluated for in vivo and in vitro inflammatory markers and endothelial cell function.

METHODS

Inflammatory markers (IL-6, matrix metalloproteinase-9 [MMP-9], vascular cell adhesion molecule-1 [VCAM-1], and von Willebrand factor [vWF]) from the incompetent great saphenous veins (GSVs) and from the systemic venous circulation were studied in 10 patients with CVD (C2s) before and after 2 months of sulodexide (2 × 500 lipasemic units/d) therapy. Serum obtained from the vein blood before and after sulodexide treatment was evaluated for in vitro cultured human umbilical vein endothelial cell function.

RESULTS

The serum collected from lower leg incompetent GSVs had significantly elevated levels of VCAM-1 (+29%, P < .001) compared with the serum from the systemic circulation. Endothelial cells exposed to the serum from the incompetent lower leg veins of the untreated CVD patients demonstrated higher stimulated synthesis of MMP-9 (+17%, P < .01), as well as increased markers of senescence (prolongation of population doubling time, β-galactosidase activity, and expression of p21 and p53 genes). CVD serum-induced senescent endothelial cells had a higher expression of genes regulating IL-6, MMP-9, VCAM-1, and vWF synthesis. The overall proinflammatory effect on endothelial cells by the serum collected from the incompetent GSVs was stronger as compared with the serum from the systemic circulation. Serum collected from the veins after sulodexide treatment caused lower levels of endothelial cell inflammatory markers as well as respective gene expression than serum obtained at the beginning of the study (before sulodexide treatment). Sulodexide application also reduced the inflammatory secretory activity of the senescent endothelial cells. Sulodexide treatment resulted in the decrease of the majority of the studied inflammatory parameters in both lower limb incompetent vein and systemic blood.

CONCLUSIONS

In patients with CVD, there are significant differences between circulating inflammatory markers analyzed from the lower leg incompetent GSV segments compared with the systemic circulation, indicating a higher inflammatory condition in CVD. Treatment with sulodexide reduces the proinflammatory and endothelial cell activation properties of the serum from patients with CVD.

CLINICAL RELEVANCE

The study documented the significant proinflammatory human vascular endothelial cell activation when exposed to the serum collected from the varicose veins as compared with the serum from the systemic circulation in patients with chronic venous disease (CVD). The inflammatory marker expression, endothelial dysfunction, and endothelial cell senescence transformation can be successfully controlled and downregulated by patients' exposure to the glycosaminoglycan (sulodexide) treatment. Further studies are needed to confirm if glycosaminoglycan application can prevent further CVD clinical progression due to potential CVD-related pathological processes' modulation and their downregulation.

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.

Insights into the Molecular Mechanism of Endothelial Glycocalyx Dysfunction during Heart Surgery

The endothelial glycocalyx (EGC) is a layer of proteoglycans (associated with glycosaminoglycans) and glycoproteins, which adsorbs plasma proteins on the luminal surface of endothelial cells. Its main function is to participate in separating the circulating blood from the inner layers of the vessels and the surrounding tissues. Physiologically, the EGC stimulates mechanotransduction, the endothelial charge, thrombocyte adhesion, leukocyte tissue recruitment, and molecule extravasation. Hence, severe impairment of the EGC has been implicated in various pathological conditions, including sepsis, diabetes, chronic kidney disease, inflammatory disorders, hypernatremia, hypervolemia, atherosclerosis, and ischemia/reperfusion injury. Moreover, alterations in EGC have been associated with altered responses to therapeutic interventions in conditions such as cardiovascular diseases. Investigation into the function of the glycocalyx has expanded knowledge about vascular disorders and indicated the need to consider new approaches in the treatment of severe endothelial dysfunction. This review aims to present the current understanding of the molecular mechanisms underlying cardiovascular diseases and to elucidate the impact of heart surgery on EGC dysfunction.

The severity of early fluid overload assessed by bioelectrical vector impedance as an independent risk factor for longer patient care after cardiac surgery

BACKGROUND AND AIMS

Fluid overload is a common postoperative complication in patients undergoing cardiac surgery. Although this condition is notably associated with relevant adverse outcomes, assessment of hydration status in clinical practice is challenging. Bioelectrical impedance vector analysis (BIVA) has emerged as a potentially effective method to monitor hydration changes, but the available evidence in critically ill patients undergoing cardiac surgery is limited and sometimes conflicting. The aim of this study was to explore by mean of BIVA the evolution over time of hydration status and its impact on relevant outcomes.

METHODS

Prospective observational study enrolling 130 patients undergoing cardiac surgery. Height normalized impedance was calculated both before surgery (baseline) and in the first five postoperative days. Relevant clinical and laboratory data were collected daily close to BIVA measurements. Length of mechanical ventilation (MV), intensive care unit (ICU) and hospital stay exceeding the 75th percentile of the study population were considered as study endpoints.

RESULTS

Compared to baseline, a significant reduction in impedance was found at first postoperative day, demonstrating a relevant fluid overload. An adjusted impedance at first postoperative day shorter than the best respective threshold was associated to longer MV (7.4 times), ICU stay (4.7 times) and hospital stay (5.6 times). A significant change in impedance and phase angle was documented throughout the observation days (p < 0.001), without returning to the baseline value. The co-existence of low impedance and high plasma osmolarity increased significantly the risk of incurring the study outcomes.

CONCLUSIONS

In patients with cardiac surgery-induced fluid overload, recovery to baseline conditions occurs slowly. A relevant early fluid overload should be considered predictive for longer time of MV, ICU and total hospital stay.

Immediate Postoperative High Syndecan-1 is Associated with Short-Term Morbidity and Mortality After Robot-Assisted Esophagectomy: A Prospective Observational Study

BACKGROUND

Disruption of the endothelial glycocalyx (EG) is associated with a poor prognosis in various clinical settings. This study aimed to determine the association between immediate postoperative serum syndecan-1 levels, a representative marker for EG degradation, and major postoperative morbidity and mortality in patients undergoing robot-assisted esophagectomy.

METHODS

Patients who underwent robot-assisted esophagectomy between 2018 and 2022 were prospectively enrolled. The primary outcome was the association between immediate postoperative syndecan-1 levels and the occurrence of major postoperative morbidity and mortality within 30 days of surgery. Patients were classified into low and high syndecan-1 groups based on the optimal cut-off value of syndecan-1 for predicting major morbidity and mortality. A multivariable logistic regression analysis was performed to investigate the risk factors for major morbidity and mortality.

RESULTS

A total of 207 patients were analyzed. Patients with high syndecan-1 levels (≥48 ng/mL) showed a significantly greater incidence of unexpected returns to the operating room and anastomotic leaks and longer durations of hospital and intensive care unit stays than patients with low syndecan-1 levels (<48 ng/mL). Immediate postoperative syndecan-1 levels ≥48 ng/mL (odds ratio [OR] 2.32, 95% confidence interval [CI] 1.23-4.76), American Society of Anesthesiologists physical status ≥III (OR 3.36, 95% CI 1.56-7.22), and current smoker (OR 4.02, 95% CI 1.52-10.61) were independently associated with major morbidity and mortality within 30 days of esophagectomy.

CONCLUSIONS

Immediate postoperative syndecan-1 levels ≥48 ng/mL could be used for the early detection of patients at high risk of complications after robot-assisted esophagectomy.

Endothelial Dysfunction in Patients Undergoing Cardiac Surgery: A Narrative Review and Clinical Implications

Cardiac surgery is one of the highest-risk procedures, usually involving cardiopulmonary bypass and commonly inducing endothelial injury that contributes to the development of perioperative and postoperative organ dysfunction. Substantial scientific efforts are being made to unravel the complex interaction of biomolecules involved in endothelial dysfunction to find new therapeutic targets and biomarkers and to develop therapeutic strategies to protect and restore the endothelium. This review highlights the current state-of-the-art knowledge on the structure and function of the endothelial glycocalyx and mechanisms of endothelial glycocalyx shedding in cardiac surgery. Particular emphasis is placed on potential strategies to protect and restore the endothelial glycocalyx in cardiac surgery. In addition, we have summarized and elaborated the latest evidence on conventional and potential biomarkers of endothelial dysfunction to provide a comprehensive synthesis of crucial mechanisms of endothelial dysfunction in patients undergoing cardiac surgery, and to highlight their clinical implications.

Severe COVID-19-A Review of Suggested Mechanisms Based on the Role of Extracellular Matrix Stiffness

The severity of COVID-19 commonly depends on age-related tissue stiffness. The aim was to review publications that explain the effect of microenvironmental extracellular matrix stiffness on cellular processes. Platelets and endothelial cells are mechanosensitive. Increased tissue stiffness can trigger cytokine storm with the upregulated expression of pro-inflammatory cytokines, such as tumor necrosis factor alpha and interleukin IL-6, and tissue integrity disruption, leading to enhanced virus entry and disease severity. Increased tissue stiffness in critically ill COVID-19 patients triggers platelet activation and initiates plague formation and thrombosis development. Cholesterol content in cell membrane increases with aging and further enhances tissue stiffness. Membrane cholesterol depletion decreases virus entry to host cells. Membrane cholesterol lowering drugs, such as statins or novel chitosan derivatives, have to be further developed for application in COVID-19 treatment. Statins are also known to decrease arterial stiffness mitigating cardiovascular diseases. Sulfated chitosan derivatives can be further developed for potential use in future as anticoagulants in prevention of severe COVID-19. Anti-TNF-α therapies as well as destiffening therapies have been suggested to combat severe COVID-19. The inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells pathway must be considered as a therapeutic target in the treatment of severe COVID-19 patients. The activation of mechanosensitive platelets by higher matrix stiffness increases their adhesion and the risk of thrombus formation, thus enhancing the severity of COVID-19.

Endothelial Mechanosensors for Atheroprone and Atheroprotective Shear Stress Signals

Vascular endothelial cells (ECs), derived from the mesoderm, form a single layer of squamous cells that covers the inner surface of blood vessels. In addition to being regulated by chemical signals from the extracellular matrix (ECM) and blood, ECs are directly confronted to complex hemodynamic environment. These physical inputs are translated into biochemical signals, dictating multiple aspects of cell behaviour and destination, including growth, differentiation, migration, adhesion, death and survival. Mechanosensors are initial responders to changes in mechanical environments, and the overwhelming majority of them are located on the plasma membrane. Physical forces affect plasma membrane fluidity and change of protein complexes on plasma membrane, accompanied by altering intercellular connections, cell-ECM adhesion, deformation of the cytoskeleton, and consequently, transcriptional responses in shaping specific phenotypes. Among the diverse forces exerted on ECs, shear stress (SS), defined as tangential friction force exerted by blood flow, has been extensively studied, from mechanosensing to mechanotransduction, as well as corresponding phenotypes. However, the precise mechanosensors and signalling pathways that determine atheroprone and atheroprotective phenotypes of arteries remain unclear. Moreover, it is worth to mention that some established mechanosensors of atheroprotective SS, endothelial glycocalyx, for example, might be dismantled by atheroprone SS. Therefore, we provide an overview of the current knowledge on mechanosensors in ECs for SS signals. We emphasize how these ECs coordinate or differentially participate in phenotype regulation induced by atheroprone and atheroprotective SS.

Impact of Anesthetic Agents on Endothelial Glycocalyx Injury during Total Knee Arthroplasty: Desflurane- vs. Propofol-Based Anesthesia-A Prospective Randomized Controlled Trial

Background

Ischemia-reperfusion injury and inflammation after tourniquet deflation in total knee arthroplasty are known to be associated with endothelial glycocalyx (EG) injury. This study is aimed at comparing EG injury between desflurane- and propofol-based anesthesia in patients undergoing total knee arthroplasty.

Materials and Methods

Patients were allocated to the desflurane group or propofol group. The opioid remifentanil was administered intraoperatively in both groups. Blood samples were obtained from the arterial line preoperatively, immediately before and 5 min after tourniquet deflation, and at 1, 6, and 24 h, postoperatively. Serum syndecan-1, cytokines (interleukin-1β, 6, 10, and tumour necrosis factor-α), and other laboratory values were investigated.

Results

Eighty patients were included in the final analysis. The change in syndecan-1 did not significantly differ between the desflurane and propofol groups (peak median level of syndecan-1; 754.5 pg/ml vs. 780.3 pg/ml, respectively, P = 0.512). Laboratory values (serum cytokines, creatinine phosphokinase, lactate dehydrogenase, and lactate levels) were also similar between the two groups. Pulmonary oxygenation was briefly improved after tourniquet deflation in the desflurane group but was similar between the two groups begging at 1 h, postoperatively.

Conclusions

The effect of desflurane was not superior to that of propofol in protecting the EG from ischemia-reperfusion injury during total knee arthroplasty. This trial is registered with Trial Registry Number NCT02756715 (http://clinicaltrials.gov).

Effect of volatile and total intravenous anesthesia on syndecan-1 shedding after minimally invasive gastrectomy: a randomized trial

This study aimed to compare the effects of volatile anesthesia and total intravenous anesthesia (TIVA) on syndecan-1 shedding in patients with gastric cancer undergoing minimally invasive gastrectomy. Patients were randomly assigned to either the Volatile (n = 68) or the TIVA (n = 68) group. Anesthesia was maintained with sevoflurane/remifentanil or propofol/remifentanil in the Volatile and TIVA groups, respectively. Serum syndecan-1 was evaluated at pre-operation, end of operation, and postoperative day (POD) 1. Inflammatory markers including white blood cell (WBC) count, neutrophil-to-lymphocyte ratio (NLR), and C-reactive protein (CRP), were also measured at pre-operation, end of operation, and POD 1, 2, 3, and 5. The TIVA group showed significantly lower levels of syndecan-1 at the end of the operation compared to the Volatile group; however, no difference was seen between the groups at POD 1. The WBC count and NLR were significantly lower in the TIVA group at the end of the operation than the Volatile group, but there were no differences between the groups at POD 1, 2, 3, and 5. CRP levels were similar between the groups at all time points. In conclusion, despite TIVA being superior to volatile anesthesia in protecting endothelial glycocalyx during the operation, both did not prevent postoperative syndecan-1 shedding after gastrectomy.

Clinical trial registration number: NCT04183296 (ClinicalTrial.gov, 03/12/2019).

[Glycocalyx as a determining factor in development of endothelial venous dysfunction and possibilities of correction thereof]

Modern vascular surgery has the data on a substantial role of the endothelium in pathogenesis of vascular diseases. Endothelial dysfunction is associated with a wide range of pathological processes including those in chronic diseases of lower-limb veins. The discovery of the endothelial glycocalyx made it possible to evaluate its role in the development of endothelial dysfunction as a trigger mechanism in impairment of venous blood flow. The understanding of the unifying role of endothelial dysfunction in pathology in various fields of medicine provides a possibility of predicting the development of serious socially significant diseases such as cardiovascular diseases, diabetes mellitus, obstetrical complications, and to correct the conditions associated therewith. The present study was aimed at carrying out a systematic literature review, thus making it possible to evaluate the role of the endothelial glycocalyx in the development of endothelial dysfunction, as well as to determine therapy with sulodexide capable of decreasing the probability of the onset of endothelial dysfunction at the expense of an anti-inflammatory, antithrombotic, and angioprotective effect on the endothelial wall.

The Glycocalyx and Its Role in Vascular Physiology and Vascular Related Diseases

Purpose

In 2007 the two senior authors wrote a review on the structure and function of the endothelial glycocalyx layer (Weinbaum in Annu Rev Biomed Eng 9:121–167, 2007). Since then there has been an explosion of interest in this hydrated gel-like structure that coats the luminal surface of endothelial cells that line our vasculature due to its important functions in (A) basic vascular physiology and (B) vascular related diseases. This review will highlight the major advances that have occurred since our 2007 paper.

Methods

A literature search mainly focusing on the role of the glycocalyx in the two major areas described above was performed using electronic databases.

Results

In part (A) of this review, the new formulation of the century old Starling principle, now referred to as the Michel–Weinbaum glycoclayx model or revised Starling hypothesis, is described including new subtleties and physiological ramifications. New insights into mechanotransduction and release of nitric oxide due to fluid shear stress sensed by the glycocalyx are elaborated. Major advances in understanding the organization and function of glycocalyx components, and new techniques for measuring both its thickness and spatio-chemical organization based on super resolution, stochastic optical reconstruction microscopy (STORM) are presented. As discussed in part (B) of this review, it is now recognized that artery wall stiffness associated with hypertension and aging induces glycocalyx degradation, endothelial dysfunction and vascular disease. In addition to atherosclerosis and cardiovascular diseases, the glycocalyx plays an important role in lifestyle related diseases (e.g., diabetes) and cancer. Infectious diseases including sepsis, Dengue, Zika and Corona viruses, and malaria also involve the glycocalyx. Because of increasing recognition of the role of the glycocalyx in a wide range of diseases, there has been a vigorous search for methods to protect the glycocalyx from degradation or to enhance its synthesis in disease environments.

Conclusion

As we have seen in this review, many important developments in our basic understanding of GCX structure, function and role in diseases have been described since the 2007 paper. The future is wide open for continued GCX research.

Trauma of major surgery: A global problem that is not going away

Globally, a staggering 310 million major surgeries are performed each year; around 40 to 50 million in USA and 20 million in Europe. It is estimated that 1-4% of these patients will die, up to 15% will have serious postoperative morbidity, and 5-15% will be readmitted within 30 days. An annual global mortality of around 8 million patients places major surgery comparable with the leading causes of death from cardiovascular disease and stroke, cancer and injury. If surgical complications were classified as a pandemic, like HIV/AIDS or coronavirus (COVID-19), developed countries would work together and devise an immediate action plan and allocate resources to address it. Seeking to reduce preventable deaths and post-surgical complications would save billions of dollars in healthcare costs. Part of the global problem resides in differences in institutional practice patterns in high- and low-income countries, and part from a lack of effective perioperative drug therapies to protect the patient from surgical stress. We briefly review the history of surgical stress and provide a path forward from a systems-based approach. Key to progress is recognizing that the anesthetized brain is still physiologically 'awake' and responsive to the sterile stressors of surgery. New intravenous drug therapies are urgently required after anesthesia and before the first incision to prevent the brain from switching to sympathetic overdrive and activating secondary injury progression such as hyperinflammation, coagulopathy, immune activation and metabolic dysfunction. A systems-based approach targeting central nervous system-mitochondrial coupling may help drive research to improve outcomes following major surgery in civilian and military medicine.

Role of albumin in the preservation of endothelial glycocalyx integrity and the microcirculation: a review

The endothelial glycocalyx comprises a complex layer of membrane-bound proteoglycans, secreted glycosaminoglycans, glycoproteins, glycolipids and bound plasma proteins such as albumin and antithrombin associated with the endothelial surface. The glycocalyx plays an important role in vascular homeostasis, regulating vascular permeability and cell adhesion, and acts as a mechanosensor for hemodynamic shear stresses; it also has antithrombotic and anti-inflammatory functions. Plasma proteins such as albumin are physiologically bound within the glycocalyx, thus contributing to stability of the layer. Albumin is the major determinant of plasma colloid osmotic pressure. In addition, albumin transports sphingosine-1-phosphate which has protective endothelial effects, acts as a free radical scavenger, and has immunomodulatory and anti-inflammatory effects. This review examines the physiological function of the endothelial glycocalyx and the role of human albumin in preserving glycocalyx integrity and the microcirculation.

Glycocalyx Degradation in Ischemia-Reperfusion Injury

The glycocalyx is a layer coating the luminal surface of vascular endothelial cells. It is vital for endothelial function as it participates in microvascular reactivity, endothelium interaction with blood constituents, and vascular permeability. Structural and functional damage to glycocalyx occurs in various disease states. A prominent clinical situation characterized by glycocalyx derangement is ischemia-reperfusion (I/R) of the whole body as well as during selective I/R to organs such as the kidney, heart, lung, or liver. Degradation of the glycocalyx is now considered a cornerstone in I/R-related endothelial dysfunction, which further impairs local microcirculation with a feed-forward loop of organ damage, due to vasoconstriction, leukocyte adherence, and activation of the immune response. Glycocalyx damage during I/R is evidenced by rising plasma levels of its principal constituents, heparan sulfate and syndecan-1. By contrast, the concentrations of these compounds in the circulation decrease after successful protective interventions in I/R, suggesting their use as surrogate biomarkers of endothelial integrity. In light of the importance of the glycocalyx in preserving endothelial cell integrity and its involvement in pathologic conditions, several promising therapeutic strategies to restore the damaged glycocalyx and to attenuate its deleterious consequences have been suggested. This review focuses on alterations of glycocalyx during I/R injury in general (to vital organs in particular), and on maneuvers aimed at glycocalyx recovery during I/R injury.

Endothelial Glycocalyx Impairment in Disease: Focus on Hyaluronan Shedding

Hyaluronan (HA) is a ubiquitous glycosaminoglycan of the extracellular matrix. It is present in the endothelial glycocalyx covering the apical surface of endothelial cells. The endothelial glycocalyx regulates blood vessel permeability and homeostasis. HA plays a central role in numerous functions of the endothelial surface layer, protecting the endothelial cells, regulating the barrier permeability, and ensuring mechanosensing, which is essential to nitric oxide production and flow-induced vasodilation. During acute injury, inflammatory conditions, or many other pathologic conditions, the endothelial glycocalyx is damaged, and its degradation is accompanied by shedding of one or more glycocalyx components into the blood. Syndecan-1, heparan sulfate, and HA are the main components whose shedding has been claimed to represent the endothelial glycocalyx state of health. This review focuses on endothelial glycocalyx HA and highlights its key roles in the functions of the endothelial glycocalyx, its shedding in several pathologic conditions such as sepsis, diabetes, chronic and acute kidney injury, ischemia/reperfusion, atherosclerosis, and inflammation, which are all accompanied by increased circulating HA levels. Plasma/serum HA level is becoming recognized as a biomarker of endothelial glycocalyx damage in select pathologies. Hyaluronidase, the main HA-degrading enzyme, and its involvement in the impairment of endothelial glycocalyx are also addressed.

Effect of Anesthetic Technique on the Occurrence of Acute Kidney Injury after Total Knee Arthroplasty

Recent studies have reported the advantages of spinal anesthesia over general anesthesia in orthopedic patients. However, little is known about the relationship between acute kidney injury (AKI) after total knee arthroplasty (TKA) and anesthetic technique. This study aimed to identify the influence of anesthetic technique on AKI in TKA patients. We also evaluated whether the choice of anesthetic technique affected other clinical outcomes. We retrospectively reviewed medical records of patients who underwent TKA between January 2008 and August 2016. Perioperative data were obtained and analyzed. To reduce the influence of potential confounding factors, propensity score (PS) analysis was performed. A total of 2809 patients and 2987 cases of TKA were included in this study. A crude analysis of the total set demonstrated a significantly lower risk of AKI in the spinal anesthesia group. After PS matching, the spinal anesthesia group showed a tendency for reduced AKI, without statistical significance. Furthermore, the spinal anesthesia group showed a lower risk of pulmonary and vascular complications, and shortened hospital stay after PS matching. In TKA patients, spinal anesthesia had a tendency to reduce AKI. Moreover, spinal anesthesia not only reduced vascular and pulmonary complications, but also shortened hospital stay.

Complement-mediated Damage to the Glycocalyx Plays a Role in Renal Ischemia-reperfusion Injury in Mice

Background

Complement activation plays an important role in the pathogenesis of renal ischemia-reperfusion (IR) injury (IRI), but whether this involves damage to the vasculoprotective endothelial glycocalyx is not clear. We investigated the impact of complement activation on glycocalyx integrity and renal dysfunction in a mouse model of renal IRI.

Methods

Right nephrectomized male C57BL/6 mice were subjected to 22 minutes left renal ischemia and sacrificed 24 hours after reperfusion to analyze renal function, complement activation, glycocalyx damage, endothelial cell activation, inflammation, and infiltration of neutrophils and macrophages.

Results

Ischemia-reperfusion induced severe renal injury, manifested by significantly increased serum creatinine and urea, complement activation and deposition, loss of glycocalyx, endothelial activation, inflammation, and innate cell infiltration. Treatment with the anti-C5 antibody BB5.1 protected against IRI as indicated by significantly lower serum creatinine (P = 0.04) and urea (P = 0.003), tissue C3b/c and C9 deposition (both P = 0.004), plasma C3b (P = 0.001) and C5a (P = 0.006), endothelial vascular cell adhesion molecule-1 expression (P = 0.003), glycocalyx shedding (tissue heparan sulfate [P = 0.001], plasma syndecan-1 [P = 0.007], and hyaluronan [P = 0.02]), inflammation (high mobility group box-1 [P = 0.0003]), and tissue neutrophil (P = 0.0009) and macrophage (P = 0.004) infiltration.

Conclusions

Together, our data confirm that the terminal pathway of complement activation plays a key role in renal IRI and demonstrate that the mechanism of injury involves shedding of the glycocalyx.

Endothelial glycocalyx: Role in body fluid homeostasis and fluid management

Endothelial glycocalyx layer (EGL) coating the luminal surface of vascular endothelium plays an essential role in maintaining the normal fluid homeostasis of the body. This highly fragile layer can be damaged by a number of pathophysiological conditions and interventions. Disease state management should be directed to maintain EGL integrity to improve patient's outcome. When intravenous (IV) fluids are used, appropriate type, rate and amount of fluid should be determined by the pathophysiology of the condition and measures to maintain the integrity of the EGL. This review depicts the structure and function of the EGL, its alteration in common pathological states and the rationale of IV fluid management to preserve EGL in such conditions.

Comparative Effects of Blood and Crystalloid Cardioplegia on Cellular Injury and Oxidative Stress in Cardiovascular Surgery

Purpose: The purpose of this study was to evaluate the effect of different cardioplegic solutions on endothelial integrity and oxidative stress in cardiovascular surgery.

Methods: In this randomized prospective study, after ethics approval and informed consent, 60 surgical patients were included. Patients undergoing coronary bypass surgery were randomized into two groups as warm blood cardioplegia (n = 30) and cold crystalloid cardioplegia (n = 30) following the cross-clamping. Measurements were performed at three time points: before induction of anesthesia (T1), at admission to intensive care unit (ICU) (T2) and at the 24th postoperative hour (T3). Besides biochemical routine hemodynamic monitoring, patients were assessed for the sialic acid (SA), ischemic-modified albumin (IMA), advanced oxide protein products (AOPPs), total thiol (SH), and free hemoglobin (fHb) level.

Results: Neither crystalloid nor blood cardioplegia led to significant changes in the AOPPs, T-SH, and SA level (p >0.05). Crystalloid cardioplegia, however, increased IMA level compared to both baseline (p <0.01) and blood cardioplegia group (p <0.05). fHb levels were transiently increased in both groups at the second-time point (p <0.001). fHb level was lower in the crystalloid group compared to that in the other group (p <0.05) at T2.

Conclusion: Cardioplegia type creates similar effects on glycocalyx integrity. However, myocardial protection could be provided with warm blood cardioplegia.