Plasma vascular endothelial growth factor level is a predictor of the severity of postoperative capillary leak syndrome in neonates undergoing cardiopulmonary bypass

Promising results of a clinical feasibility study: CIRBP as a potential biomarker in pediatric cardiac surgery

Objective

Cold-inducible RNA binding Protein (CIRBP) has been shown to be a potent inflammatory mediator and could serve as a novel biomarker for inflammation. Systemic inflammatory response syndrome (SIRS) and capillary leak syndrome (CLS) are frequent complications after pediatric cardiac surgery increasing morbidity, therefore early diagnosis and therapy is crucial. As CIRBP serum levels have not been analyzed in a pediatric population, we conducted a clinical feasibility establishing a customized magnetic bead panel analyzing CIRBP in pediatric patients undergoing cardiac surgery.

Methods

A prospective hypothesis generating observational clinical study was conducted at the German Heart Center Berlin during a period of 9 months starting in May 2020 (DRKS00020885, https://drks.de/search/de/trial/DRKS00020885). Serum samples were obtained before the cardiac operation, upon arrival at the pediatric intensive care unit, 6 and 24 h after the operation in patients up to 18 years of age with congenital heart disease (CHD). Customized multiplex magnetic bead-based immunoassay panels were developed to analyze CIRBP, Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Interleukin-8 (IL-8), Interleukin-10 (IL-10), Monocyte chemotactic protein 1 (MCP-1), Syndecan-1 (SDC-1), Thrombomodulin (TM), Vascular endothelial growth factor (VEGF-A), Angiopoietin-2 (Ang-2), and Fibroblast growth factor 23 (FGF-23) in 25 µl serum using the Luminex MagPix® system.

Results

19 patients representing a broad range of CHD (10 male patients, median age 2 years, 9 female patients, median age 3 years) were included in the feasibility study. CIRBP was detectable in the whole patient cohort. Relative to individual baseline values, CIRBP concentrations increased 6 h after operation and returned to baseline levels over time. IL-6, IL-8, IL-10, and MCP-1 concentrations were significantly increased after operation and except for MCP-1 concentrations stayed upregulated over time. SDC-1, TM, Ang-2, as well as FGF-23 concentrations were also significantly increased, whereas VEGF-A concentration was significantly decreased after surgery.

Discussion

Using customized magnetic bead panels, we were able to detect CIRBP in a minimal serum volume (25 µl) in all enrolled patients. To our knowledge this is the first clinical study to assess CIRBP serum concentrations in a pediatric population.

Plasma and Urinary FGF-2 and VEGF-A Levels Identify Children at Risk for Severe Bleeding after Pediatric Cardiopulmonary Bypass: A Pilot Study

Severe bleeding after cardiothoracic surgery with cardiopulmonary bypass (CPB) is associated with increased morbidity and mortality in adults and children. Fibroblast Growth Factor-2 (FGF-2) and Vascular Endothelial Growth Factor-A (VEGF-A) induce hemorrhage in murine models with heparin exposure. We aim to determine if plasma and urine levels of FGF-2 and VEGF-A in the immediate perioperative period can identify children with severe bleeding after CPB. We performed a prospective, observational biomarker study in 64 children undergoing CPB for congenital heart disease repair from June 2015 - January 2017 in a tertiary pediatric referral center. Primary outcome was severe bleeding defined as ≥ 20% estimated blood volume loss within 24-hours. Independent variables included perioperative plasma and urinary FGF-2 and VEGF-A levels. Analyses included comparative (Wilcoxon rank sum, Fisher's exact, and Student's t tests) and discriminative (receiver operator characteristic [ROC] curve) analyses. Forty-eight (75%) children developed severe bleeding. Median plasma and urinary FGF-2 and VEGF-A levels were elevated in children with severe bleeding compared to without bleeding (preoperative: plasma FGF-2 = 16[10-35] vs. 9[2-13] pg/ml; urine FGF-2= 28[15-76] vs. 14.5[1.5-22] pg/mg; postoperative: plasma VEGF-A = 146[34-379] vs. 53 [0-134] pg/ml; urine VEGF-A = 132 [52-257] vs. 45[0.1-144] pg/mg; all p < 0.05). ROC curve analyses of combined plasma and urinary FGF-2 and VEGF-A levels discriminated severe postoperative bleeding (AUC: 0.73-0.77) with mean sensitivity and specificity above 80%. We conclude that the perioperative plasma and urinary levels of FGF-2 and VEGF-A discriminate risk of severe bleeding after pediatric CPB.

Protective Effects of Cucurbitacin B on Acute Lung Injury Induced by Sepsis in Rats

Background

The aim of this study was to investigate the protective effects of cucurbitacin B (CuB) on sepsis-induced acute lung injury (ALI) in rats.

Material/Methods

An ALI model was made by cecal ligation and puncture (CLP) in SD rats. Rats were randomly divided into 5 groups (n=15 per group): animals undergoing a sham CLP (sham group); animals undergoing CLP (CLP control group); animals undergoing CLP and treated with CuB at 1 mg/kg of body weight (bw) (low-dose CuB [L-CuB] group), animals undergoing CuB at 2 mg/kg of bw (mid-dose CuB [M-CuB] group); and animals undergoing CuB at 5 mg/kg of bw (high-dose CuB [H-CuB] group). Samples of blood and lung tissue were harvested at different time points (6, 12, and 24 hour post-CLP surgery) for the detection of indicators which represented ALI. Five rats were respectively sacrificed at each time point. Pathological changes of lung tissue were observed by H&E staining. Another 50 rats were distributed into the same five groups to record the 72 hour survival rates.

Results

Treatment with CuB significantly increased the blood gas PaO2 levels and decreased lung wet/dry (W/D) ratio (p<0.05). It significantly reduced protein concentration, accumulation of the inflammatory cells, and levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), (p<0.05), in the bronchoalveolar lavage fluid (BALF). Pulmonary pathological damage and survival rates at 72 hours were found to be effectively improved by CuB. In addition, CuB performed its pulmonary protection effects in a dose-depended manner.

Conclusions

CuB can effectively improve the pulmonary gas exchange function, reduce pulmonary edema, and inhibit the inflammatory response in the lung, revealing that CuB may serve as a potential therapeutic strategy for sepsis-induced ALI.

[Idiopathic and secondary capillary leak syndromes: A systematic review of the literature]

PURPOSE

The capillary leak syndrome (CLS) is a rare condition characterized by the onset of hypotension, edema, hemoconcentration and hypoalbuminemia. CLS can be idiopathic (Clarkson's disease) or secondary to various conditions and treatments. Here, we review the clinical and biological features, pathophysiology, causes and treatment of this rare condition.

METHODS

We performed a systematic review of the literature (Medline database through February 2014) to identify all articles about CLS. The relevant references were selected by two independent authors.

RESULTS

Secondary CLSs are mostly due to malignant hematological diseases, viral infections, and treatments such as chemotherapies and therapeutic growth factors. Diagnosis of idiopathic CLS is made by exclusion of secondary diseases, especially as a serum monoclonal immunoglobulin is present, or when there is a relapsing disease, no initial lung involvement or preserved consciousness despite low blood pressure. Acute episodes are treated with vasopressor therapy and judicious fluid replacement. Between episodes, patients with Clarkson's disease may be treated with intravenous immunoglobulins. CLS is a severe disease with significantly impaired prognosis.

CONCLUSION

Clarification of the pathophysiological mechanisms of CLS is essential to improve the prognosis of this rare disease with more targeted treatments.

Basics of fluid and blood transfusion therapy in paediatric surgical patients

Perioperative fluid, electrolyte and blood transfusion therapy for infants and children can be confusing due the numerous opinions, formulas and clinical applications, which can result in a picture that is not practical and is often misleading. Perioperatively, crystalloids, colloids and blood components are required to meet the ongoing losses and for maintaining cardiovascular stability to sustain adequate tissue perfusion. Recently controversies have been raised regarding historically used formulas and practices of glucose containing hypotonic maintenance crystalloid solutions for perioperative fluid therapy in children. Paediatric intraoperative transfusion therapy, particularly the approach to massive blood transfusion (blood loss ≥ one blood volume) can be quite complex because of the unique relationship between the patient's blood volume and the volume of the individual blood product transfused. A meticulous fluid, electrolyte and blood transfusion management is required in paediatric patients perioperatively because of an extremely limited margin for error. This article reviews the basic concepts in perioperative fluid and blood transfusion therapy for paediatric patients, along with recent recommendations. For this review, Pubmed, Ovid MEDLINE, HINARI and Google scholar were searched without date restrictions. Search terms included the following in various combinations: Perioperative, fluid therapy, paediatrics, blood transfusion, electrolyte disturbances and guidelines. Only articles with English translation were used.

Perioperative crystalloid and colloid fluid management in children: where are we and how did we get here?

It has been more than 50 yr since the landmark article in which Holliday and Segar (Pediatrics 1957;19:823-32) proposed the rate and composition of parenteral maintenance fluids for hospitalized children. Much of our practice of fluid administration in the perioperative period is based on this article. The glucose, electrolyte, and intravascular volume requirements of the pediatric surgical patient may be quite different than the original population described, and consequently, use of traditional hypotonic fluids proposed by Holliday and Segar may cause complications, such as hyperglycemia and hyponatremia, in the postoperative surgical patient. There is significant controversy regarding the choice of isotonic versus hypotonic fluids in the postoperative period. We discuss the origins of perioperative fluid management in children, review the current options for crystalloid fluid management, and present information on colloid use in pediatric patients.

Vascular endothelial growth factor as marker for tissue hypoxia and transfusion need in anemic infants: a prospective clinical study

OBJECTIVE

Oxygen-carrying capacity of blood is reduced in anemic infants because of low hemoglobin levels. Red blood cell transfusions become necessary if low hematocrit causes tissue hypoxia. No reliable parameters exist for detecting chronic tissue hypoxia. Vascular endothelial growth factor is upregulated by hypoxia; hence, elevated vascular endothelial growth factor levels may be a marker for tissue hypoxia and may indicate the need for red blood cell transfusions.

METHODS

In a prospective study, plasma vascular endothelial growth factor levels were measured in 3 groups of infants suspected of requiring red blood cell transfusions to find a vascular endothelial growth factor cutoff value indicative of tissue hypoxia. The 3 groups were acute anemic (an episode of acute bleeding [hematocrit drop > 5%] per day); chronic anemic (hematocrit drop < 5% per day); and nontransfused (hematocrit drop < 5% per day) but not meeting clinical criteria for a transfusion. Blood was sampled before transfusion and again 48 hours after transfusion if required. Plasma vascular endothelial growth factor and erythropoietin concentrations were measured.

RESULTS

Vascular endothelial growth factor concentrations were lower in acutely anemic compared with chronically anemic infants, whereas erythropoietin levels did not differ between these groups. The vascular endothelial growth factor concentration was <140 pg/mL in all acutely anemic infants, and this was deemed the threshold level indicating sufficient tissue oxygenation in subsequent analysis. We found that 30% of chronically anemic and 43% of nontransfused infants had vascular endothelial growth factor levels of >140 pg/mL. In transfused infants, with elevated vascular endothelial growth factor levels, red blood cell transfusion resulted in lowering of vascular endothelial growth factor concentrations.

CONCLUSIONS

Vascular endothelial growth factor concentrations of >140 pg/mL may indicate insufficient oxygen delivery to tissues and may serve as a marker of the need for transfusion or of tissue hypoxia in other diseases.

Plasma angiopoietin-2 levels increase in children following cardiopulmonary bypass

OBJECTIVE

The aim was to investigate the effects of cardiopulmonary bypass (CPB) on plasma levels of the vascular growth factors, angiopoietin (angpt)-1, angpt-2, and vascular endothelial growth factor (VEGF).

DESIGN

The design was a prospective, clinical investigation.

SETTING

The setting was a 12-bed pediatric cardiac intensive care unit of a tertiary children's medical center.

PATIENTS

The patients were 48 children (median age, 5 months) undergoing surgical correction or palliation of congenital heart disease who were prospectively enrolled following informed consent.

INTERVENTIONS

There were no interventions in this study.

MEASUREMENTS AND RESULTS

Plasma samples were obtained at baseline and at 0, 6, and 24 h following CPB. Angpt-1, angpt-2, and VEGF levels were measured via commercial ELISA. Angpt-2 levels increased by 6 h (0.95, IQR 0.43-2.08 ng mL(-1) vs. 4.62, IQR 1.16-6.93 ng mL(-1), P < 0.05) and remained significantly elevated at 24 h after CPB (1.85, IQR 0.70-2.76 ng mL(-1); P < 0.05). Angpt-1 levels remained unchanged immediately after CPB, but were significantly decreased at 24 h after CPB (0.64, IQR 0.40-1.62 ng mL(-1) vs. 1.99, IQR 1.23-2.63 ng mL(-1), P < 0.05). Angpt-2 levels correlated significantly with cardiac intensive care unit (CICU) length of stay (LOS) and were an independent predictor for CICU LOS on subsequent multivariate analysis.

CONCLUSIONS

Angpt-2 appears to be an important biomarker of adverse outcome following CPB in children.

Factors prolonging length of stay in the cardiac intensive care unit following the arterial switch operation

The arterial switch operation has become the preferred procedure for surgical management of transposition, defined on the basis of concordant atrioventricular and discordant ventriculo-arterial connections. We conducted a retrospective evaluation of our experience in 61 infants with this segmental combination, seen from January, 1997, to July, 2003, in order to determine the factors that are associated with a prolonged postoperative course. Factors independently associated with a prolonged postoperative stay in the cardiac intensive care unit included prematurity, difficulty in feeding, capillary leak, need for preoperative inotropic support, and postoperative infectious complications. Future research is warranted designed to minimize the impact of capillary leak and postoperative infectious complications. In addition, based on these results, our practice has evolved to initiate enteral feedings in the preoperative period if feasible, with such enteral feedings resumed as soon as possible following surgery.

The role of vascular endothelial growth factor leading to vascular leakage in children with dengue virus infection

Increased vascular permeability is the main aetiology for hypovolaemic shock and circulatory failure in dengue haemorrhagic fever (DHF).

AIM

To investigate the role of vascular endothelial growth factor (VEGF) in the pathogenesis of DHF.

METHODS

Serum samples from 41 patients [15 dengue fever (DF), 26 DHF] with serologically confirmed dengue virus infection during the febrile, toxic, convalescent stages and at follow-up were analysed for VEGF. Plasma samples from an additional 27 children (16 DF and 11 DHF) during the febrile, toxic stages and at 4-week follow-up and from eight healthy controls were analysed for VEGF.

RESULTS

Serum and plasma VEGF levels were not elevated during the febrile or toxic stages of dengue virus infection and did not differ between patients with DF and DHF.

CONCLUSION

Plasma leakage in patients with DHF cannot be explained by elevation of VEGF during the toxic stage of the illness.

Virus-induced decline in soluble vascular endothelial growth receptor 2 is associated with plasma leakage in dengue hemorrhagic Fever

Some individuals infected with dengue virus develop dengue hemorrhagic fever (DHF), a viral hemorrhagic disease characterized by a transient period of localized plasma leakage. To determine the importance of vascular endothelial growth factor A (VEGF-A) in this syndrome, we compared plasma levels of VEGF-A and the soluble forms of its receptors in patients with DHF to patients with dengue fever (DF), a milder form of dengue virus infection without plasma leakage. We observed a rise in the plasma levels of free, but not total VEGF-A in DHF patients at the time of plasma leakage. This was associated with a decline in the soluble form of VEGF receptor 2 (VEGFR2) and VEGF-soluble VEGFR2 complexes, but not the soluble form of VEGFR1. The severity of plasma leakage in patients inversely correlated with plasma levels of soluble VEGFR2. In vitro, dengue virus suppressed soluble VEGFR2 production by endothelial cells but up-regulated surface VEGFR2 expression and promoted response to VEGF stimulation. In vivo, plasma viral load correlated with the degree of decline in plasma soluble VEGFR2. These results suggest that VEGF regulates vascular permeability and its activity is controlled by binding to soluble VEGFR2. Dengue virus-induced changes in surface and soluble VEGFR2 expression may be an important mechanism of plasma leakage in DHF.

Influence of Volume Replacement with Colloids versus Crystalloids in Neonates on Venoarterial Extracorporeal Membrane Oxygenation on Fluid Retention, Fluid Balance, and ECMO Runtime

In this retrospective study, we compared the effects of colloid versus crystalloid fluid replacement on the clinical signs of capillary leakage syndrome in 30 neonates with pulmonary hypertension due to meconium aspiration syndrome on venoarterial membrane oxygenation (VA-ECMO). Before 2000, 15 neonates received volume replacement with a pasteurized plasma protein solution (3.8% albumin); after 2000, 15 neonates received normal saline. Patient characteristics and pre-ECMO values did not differ between the two groups. Total fluid balance was also equal. Diuretic use was significantly higher in the colloid group (p < 0.001). The chest wall soft-tissue index was significantly higher in the crystalloid group (p < 0.005), as were the ventilator settings at the end of the ECMO runtime (p < 0.05). Serum colloid osmotic pressure, albumin, urea nitrogen, and creatinine were significantly higher in the colloid group (p < 0.0001, < 0.0001, < 0.001, and < 0.05, respectively). Duration of VA-ECMO, of artificial ventilation after ECMO treatment, and the mortality rate did not differ between the two groups. We conclude that volume replacement with crystalloids in neonates on VA-ECMO aggravated the edema in a preexisting situation of capillary leakage syndrome, whereas volume replacement with colloids could impair the kidney function.

Plasma vascular endothelial growth factor in severe sepsis

Vascular endothelial growth factor (VEGF) is a potent vascular permeability factor. The development of capillary leak is common in septic patients, and several sepsis-associated mediators may induce VEGF production. The potential role of VEGF during sepsis has not been studied to date. The aim of the study was first to assess whether circulating VEGF levels increase during sepsis, and second, to examine whether plasma VEGF levels are associated with disease severity. VEGF levels were measured in serial plasma samples of 18 patients with severe sepsis and in 40 healthy controls. VEGF levels were correlated to clinical signs and symptoms. VEGF levels were significantly elevated in sepsis patients compared with healthy controls (134 vs. 55 pg/mL; P <0.001). Serum albumin levels used as an indirect measure of vascular leak were decreased in septic patients. Increased plasma VEGF levels at study entry were correlated to severity of multiple organ dysfunction during the course of disease (Pearson correlation coefficient r=0.75; P=0.001). Moreover, maximum VEGF levels in nonsurvivors were significantly higher than those in survivors (P=0.018). These data show that plasma VEGF levels are elevated during severe sepsis. Furthermore, our data indicate that plasma VEGF levels are associated with disease severity and mortality. Further study of the potential role of VEGF in the development of sepsis-associated capillary leak is indicated.

Alterations in plasma angiogenic growth factor concentrations after coronary artery bypass graft surgery: relationships with post-operative complications

To determine whether angiogenic growth factor levels are altered during and after cardiac surgery, plasma concentrations of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and transforming growth factor beta1 (TGFbeta1) were measured in 32 patients undergoing coronary artery bypass graft (CABG) surgery with extracorporeal circulation (ECC). EGF levels significantly decreased during ECC and remained low until the 24th post-operative hour with no difference between complicated and uncomplicated patients. TGFbeta1 and bFGF concentrations significantly increased at the end of ECC and after cross-clamp release, and returned to pre-operative values at the 6th post-operative hour suggesting that the source of these elevations are the lungs and heart. After cross-clamp release bFGF levels but not TGFbeta1 ones were higher in patients with respiratory impairments. VEGF values increased significantly at the 6th and 24th post-operative hours. At the 24th post-operative hour plasma VEGF levels were higher in patients with cardiovascular and hematological impairments. In conclusion, these results highlight that the angiogenic network is profoundly altered in patients undergoing cardiopulmonary bypass as previously demonstrated for lipidic, cytokine and haematopoietic growth factor ones and identify an association between specific post-CABG complications and systemic release of bFGF and VEGF.

Systemic microvascular leak in an in vivo rat model of ventilator-induced lung injury

Positive pressure mechanical ventilation has significant systemic effects, but the systemic effects associated with ventilator-induced lung injury (VILI) are unexplored. We hypothesized that VILI would cause systemic microvascular leak that is dependent on nitric oxide synthase (NOS) expression. Rats were ventilated with room air at 85 breaths/minute for 2 hours with either VT 7 or 20 ml/kg. Kidney microvascular leak, which was assessed by measuring 24-hour urine protein and Evans blue dye, was used as a marker of systemic microvascular leak. A significant microvascular leak occurred in both lung and kidney with large VT (20 ml/kg) ventilation. Injection of 0.9% NaCl corrected the hypotension and the decreased cardiac output related to large VT, but it did not attenuate microvascular leak of lung and kidney. Serum vascular endothelial growth factor was significantly elevated in large VT groups. Endothelial NOS expression significantly increased in the lung and kidney tissue with large VT ventilation but not inducible NOS. The NOS inhibitor, N-nitro-L-arginine methyl ester, attenuated the microvascular leak of lung and kidney and the proteinuria with large VT ventilation. Endothelial NOS may mediate the systemic microvascular leak of the present model of VILI.

Pulmonary vascular endothelial growth factor and nitric oxide interaction during total cardiopulmonary bypass in neonatal pigs

OBJECTIVE

Lung injury after cardiopulmonary bypass includes pulmonary hypertension and lung edema. Both complications are related to endothelial pulmonary vascular dysfunction, leukocyte sequestration, and increased capillary permeability. This study was done in an attempt to better define the endothelial dysfunction and the cause of edema.

METHODS

Twenty-five neonatal piglets were subjected to total cardiopulmonary bypass for 90 minutes without crossclamping of the aorta. After weaning from cardiopulmonary bypass, they were allowed to survive 2 hours, at which time they were killed. Preoperative and postoperative hemodynamic studies, lung (n = 16) and muscular (n = 5) vascular endothelial growth factor contents, and exhaled nitric oxide (n = 8) were recorded. Immediately after the animals were killed, pulmonary arterial rings were obtained from 12 piglets and mounted in organ chamber for assessment of endothelial function with receptor-dependent (acetylcholine) or non-receptor-dependent (calcium ionophore A23187) studies and compared with control pulmonary arterial rings. The left lungs of 13 piglets were mounted in isolated perfused lung chambers for filtration coefficient assessment and comparison with control preparations.

RESULTS

After cardiopulmonary bypass, pulmonary vascular resistance increased from 953.7 +/- 302.6 dyne x s x cm(-5) to 1973.6 +/- 925.4 dyne x s x cm(-5) (P =.03). This was associated with an increase in lung vascular endothelial growth factor content from 91.07 +/- 5.314 pg/100 mg tissue to 151.6 +/- 11.4 pg/100 mg tissue (P <.0001), an increase in muscle vascular endothelial growth factor from 76.02 +/- 11.53 pg/100 mg tissue to 81.58 +/- 7.7 pg/100 mg tissue (P not significant), and a decrease in exhaled nitric oxide from 6 +/- 1.7 ppb to 3.12 +/- 1.4 ppb (P =.003). The filtration coefficient was statistically significantly higher after cardiopulmonary bypass than in control preparations (0.259 +/- 0.02 vs 0.525 +/- 0.07, P <.0001). Variations in lung vascular endothelial growth factor accumulation were statistically significantly higher than in muscular vascular endothelial growth factor accumulation (60.5 +/- 9.1 vs 5.5 +/- 5.9, P =.0008). In addition, a statistically significant correlation was found between postbypass lung vascular endothelial growth factor and lung filtration coefficient (P =.0058), as well as between change in lung vascular endothelial growth factor and change in lung filtration coefficient (P =.03). Pulmonary vascular endothelial receptor-dependent (acetylcholine) function was statistically significantly blunted after bypass relative to control values (15.44% +/- 4.8% vs 55.5% +/- 5.96% of maximal relaxation, P =.0001), whereas non-receptor-dependent endothelial function was unaffected by cardiopulmonary bypass (110.77% +/- 8.9% vs 120.63% +/- 15.46% of maximal relaxation, P not significant).

CONCLUSIONS

These findings suggest that lung ischemia that occurs during cardiopulmonary bypass affects the signal transduction from membrane receptors to intracellular calcium mobilization and nitric oxide synthase activation. Lung edema after bypass is probably due in part to lung accumulation of vascular endothelial growth factor, a finding that was not found in systemic muscular nonischemic territories.