Global fibrinolytic capacity in early respiratory distress syndrome: a pilot study

Relationship between platelet count and severity of neonatal respiratory distress syndrome

BACKGROUND

Neonatal respiratory distress syndrome (NRDS) is a primary cause of morbidity and mortality in premature infants. Platelets have a unique role in lung repair and remodeling. This study aimed to determine the relationship between platelet count and NRDS severity.

METHODS

The study included 234 newborns diagnosed with NRDS from January 2019 to August 2023. This study employed two methods of grouping: the first based on platelet count, dividing participants into thrombocytopenia (platelet count < 150 × 109/L, n = 50) and non-thrombocytopenia groups (platelet count ≥ 150 × 109/L, n = 184), and the second based on the severity of NRDS, categorizing them into severe (n = 24) and mild-moderate (n = 210) groups. Within the first grouping method, the thrombocytopenia group was further subdivided into moderate-severe group (platelet count < 100 × 109/L, n = 4) and mild group (platelet count was between 100.0 × 109/L and 150.0 × 109/L, n = 46). This study aimed to analyze the clinical characteristics of NRDS with thrombocytopenia, explore the correlation between platelet count and clinical indicators of NRDS. Binary Logistic regression analysis was employed to identify independent risk factors for thrombocytopenia in NRDS.

RESULTS

A higher proportion of newborns in the severe group exhibited thrombocytopenia (severe group = 41.7%, mild-moderate group = 19.0%). Hospital stay, ventilation time, oxygen therapy duration were longer in the thrombocytopenia group compared to the non-thrombocytopenia group. Hospital stay, ventilation time, oxygen therapy duration, chest radiography score, and C-reactive protein (CRP) levels were inversely associated with platelet count. Conversely, Apgar scores at 1 and 5 min, gestational age, and birth weight showed positive correlations with platelet count. Point-biserail correlation showed that thrombocytopenia was more likely to occur in newborns whose mothers had gestational hypertension, and the lower platelet count, the more severe NRDS. Oxygen therapy duration, birth weight < 1500 g, gestational hypertension and CRP levels emerged as independent risk factors for thrombocytopenia in NRDS. All differences were statistically significant (p all < 0.05).

CONCLUSION

NRDS accompanied by thrombocytopenia indicates a more severe condition and poorer clinical outcomes. It is hypothesized that NRDS with thrombocytopenia involves a complex multifactorial etiology, including severe lung inflammation.

Association of low ficolin-2 concentration in cord serum with respiratory distress syndrome in preterm newborns

Introduction

Ficolin-2 is a serum pattern recognition molecule, involved in complement activation via the lectin pathway. This study aimed to investigate the association of ficolin-2 concentration in cord blood serum with complications related to premature birth.

Methods

546 premature neonates were included. The concentration of ficolin-2 in cord blood serum was determined by a sandwich TRIFMA method. FCN2 genetic variants were analysed with RFLP-PCR, allele-specific PCR, Sanger sequencing or allelic discrimination using TaqMan probes method.

Findings

Cord blood serum ficolin-2 concentration correlated positively with Apgar score and inversely with the length of hospitalisation and stay at Neonatal Intensive Care Unit (NICU). Multivariate logistic regression analysis indicated that low ficolin-2 increased the possibility of respiratory distress syndrome (RDS) diagnosis [OR=2.05, 95% CI (1.24-3.37), p=0.005]. Median ficolin-2 concentration was significantly lower in neonates with RDS than in premature babies without this complication, irrespective of FCN2 gene polymorphisms localised to promoter and 3'untranslated regions: for patients born <33 GA: 1471 ng/ml vs. 2115 ng/ml (p=0.0003), and for patients born ≥33 GA 1610 ng/ml vs. 2081 ng/ml (p=0.012). Ficolin-2 level was also significantly lower in neonates requiring intubation in the delivery room (1461 ng/ml vs. 1938 ng/ml, p=0.023) and inversely correlated weakly with the duration of respiratory support (R=-0.154, p<0.001). Interestingly, in the neonates born at GA <33, ficolin-2 concentration permitted differentiation of those with/without RDS [AUC=0.712, 95% CI (0.612-0.817), p<0.001] and effective separation of babies with mild RDS from those with moderate/severe form of the disease [AUC=0.807, 95% CI (0.644-0.97), p=0.0002].

Conclusion

Low cord serum ficolin-2 concentration (especially in neonates born at GA <33 weeks) is associated with a higher risk of developing moderate/severe RDS, requiring respiratory support and intensive care.

Rotational Thromboelastometry in Neonates Admitted to a Neonatal Intensive Care Unit: A Large Cross-sectional Study

The aim of the present study was to assess the coagulation profile in neonatal critical illness using rotational thromboelastometry (ROTEM), and to investigate its association with disease severity and its potential prognostic role in this clinical setting. Over a period of 67 months (July 2014-February 2020) 423 critically ill neonates with confirmed or suspected sepsis, perinatal hypoxia, or respiratory distress syndrome, hospitalized in our neonatal intensive care unit were included in the study. Demographic, clinical, and laboratory data were recorded on admission day and arterial blood was analyzed on ROTEM analyzer using the standard extrinsically activated rotational thromboelastometry assay (EXTEM). Neonatal illness severity scores (Modified NEOMOD [Neonatal Multiple Organ Dysfunction] and SNAPPE [Score for Neonatal Acute Physiology with Perinatal Extension]) were calculated at the same time as ROTEM analysis. Mortality during in-hospital stay was the main outcome measure. Multivariable analyses showed that a 10 mm decrease in EXTEM clot amplitude recorded at 10 minutes (A10) is significantly associated with a higher mortality (odds ratio [OR] = 1.69, 95% confidence interval [CI]: 1.33-2.08). Higher modified NEOMOD (OR = 1.36, 95% CI: 1.26-1.47) and higher SNAPPE scores (OR = 1.06, 95% CI: 1.04-1.08) were also associated with increased mortality. The CT and A10 variables demonstrated the best prognostic performance among the EXTEM parameters for mortality (area under the curve [AUC] = 0.78; 95% CI: 0.69-0.86 and AUC = 0.76; 95% CI: 0.66-0.85, respectively), showing an optimal cut-off CT ≥63 seconds and A10 ≤37 mm. Using optimal cut-off values of the EXTEM parameters for prediction of mortality, neonates with CT ≥63 seconds were 7.4 times more likely to die (OR = 7.40, 95% CI: 3.50-15.65), while neonates with A10 ≤37 mm were 5.8 times more likely to die (OR = 5.88, 95% CI: 2.94-12.50). An EXTEM hypocoagulable profile on disease onset was shown to be an independent risk factor for in-hospital mortality in neonatal critical illness.

Global assays of fibrinolysis

Fibrinolysis is an important and integral part of the hemostatic system. Acting as a balance to blood coagulation, the fibrinolytic system protects the body from unwanted thrombus formation and occlusion of blood vessels. As long as blood coagulation and fibrinolysis remain in equilibrium, response to injury, such as vessel damage, is appropriately regulated. However, alterations in this balance may lead to thrombosis or bleeding. A variety of methods have been proposed to assess fibrinolytic activity in blood or its components, but due to the complexity of the system, the design of a "gold standard" assay that reflects overall fibrinolysis has remained an elusive goal. In this review, we describe the most commonly used methods that have been described, such as thromboelastography (TEG and ROTEM), global fibrinolytic capacity in plasma and whole blood, plasma turbidity methods, simultaneous thrombin and plasmin generation assays, euglobulin clot lysis time and fibrin plate methods. All of these assays have strengths and limitations. We suggest that some methods may be preferable for detecting hypofibrinolytic conditions, whereas others may be better for detecting hyperfibrinolytic states.

Global Fibrinolytic Capacity Increased Exponentially in Metastatic Colorectal Cancer

Colorectal cancers are one of the most common malignancies associated with coagulation abnormalities ranging from asymptomatic laboratory changes to massive thromboembolism or hemorrhage. It was previously shown that global fibrinolytic was increased in non-metastatic colorectal cancer. In this study global fibrinolytic capacity was measured in patients with colorectal cancer and metastatic liver disease, which always more commonly displays various coagulation disorders. Nineteen patients with biopsy-proven colorectal cancer, 30 patients with metastatic colorectal cancer, and 20 healthy control subjects were involved into the study. Using standart silicated fibrin pellets and tissue plasminogen activator, fibrinolytic capacity of the plasmas was detected with the amount of D-dimer produced before the reaction was stopped by adding aprotinin to the medium. Mean global fibrinolytic capacity (GFC) was increased to higher levels in patients with metastatic disease compared to levels in non-metastatic disease (p<0.05). Fibrinogen/GFC ratio correlated to the increase of D-dimer levels. Global fibrinolytic capacity was much higher in metastatic disease, reflecting a progression to overt disseminated intravascular coagulation.

Long-term ongoing coagulopathy in premature infants with respiratory distress syndrome

The previously reported activated intravascular coagulation system in the acute phase of respiratory distress syndrome (RDS) has not been evaluated in the long term. We assessed the activities of coagulation system of a cohort of premature infants with RDS in comparison with healthy premature infants (HPIs), healthy mature infants (HMIs), and pediatric laboratory controls over a 6-month period. Cord and venous blood samples were taken at birth, at the first month and sixth month. Protein C (PC), free protein S (f-PS), and antithrombin (AT) activities, thrombin-antithrombin (TAT) complex, prothrombin fragment 1 + 2 (PF1 + 2), and fibrinogen levels were measured. Mean PC, f-PS, d-dimer, and fibrinogen values were similar at all periods for HPI and RDS groups. Low neonatal anticoagulant proteins increased within 6 months in HMI and HPI groups. However, in RDS group, the AT activity remained significantly lower together with significantly higher TAT and PF1 + 2 levels both at the first month and at sixth month, suggesting a long-term consumption coagulopathy.

Global Fibrinolytic Capacity in Neonatal Sepsis

In this study, we studied global fibrinolytic capacity (GFC) in newborn infants with sepsis. Sixty-one newborn infants, admitted to neonatal intensive care unit at Yuzuncu Yil University Hospital were enrolled in this study. White blood cell count, immature (I) / mature (M) neutrophil ratios, prothrombin time, and d-dimer levels were significantly higher in patient group than those of control group ( P < .05). We found GFC to be significantly lower in the patient group compared to the control group ( P < .05). The GFC value was negatively correlated to the Tollner scores but this correlation was not statistically significant ( r = −.267, P = .095). Our findings showed that GFC decreases in severe neonatal sepsis; therefore, we suggest that GFC may be used for prognosis or in the early prediction of severe sepsis rather than the diagnosis of neonatal sepsis.

Plasminogen Activator Inhibitor I 4G/5G Polymorphism in Neonatal Respiratory Distress Syndrome

Fibrin monomers inhibit surfactant function. 4G/5G insertion/deletion polymorphism plays an important role in the regulation of plasminogen activator inhibitor 1 (PAI-1) gene expression. To examine the genotype distribution of PAI-1 polymorphism in 60 infants with respiratory distress syndrome (RDS) and 53 controls, an allele-specific polymerase chain reaction (PCR) was used. The proportion of 4G/4G, 4G/5G, and 5G/5G genotypes did not differ statistically between the RDS and control groups (P > .05). Having PAI-1 4G/4G genotype polymorphism appears to increase the risk of RDS (odds ratio [OR] =1.5; 95% confidence interval [CI], 0.5-4.3), although it was not statistically significant. No relation was found between the PAI-1 4G/5G polymorphisms and RDS, but there was an increased risk associated with the 4G variant of the PAI-1 gene. We believe that our findings of increased 4G allele of the PAI-1 gene in infants with RDS would also help to clarify the pathogenesis of RDS.

Role of protein Z and protein C in neonates with respiratory distress syndrome in Egypt (experience of one centre)

The aim of this study is to evaluate Protein Z (PTZ) and protein C (PTC) levels in newborns suffering from RDS, healthy preterm and full term newborns and to compare PTZ serum levels in RDS preterm infants with healthy preterm before and after recovery. Sixty newborn infants, recruited from the neonatal unit, were enrolled in the study and divided into 3 groups: Group (I): 20 preterm with RDS, Group (II): 20 healthy preterm control newborns (CPT) and Group (III): 20 healthy full term control newborns (CFT). Protein Z and C were measured using ELISA kits. The results of the study showed lower levels of protein Z were obtained in RDS group compared to preterm controls whose levels were significantly lower than in full-term controls. A significant increase in PTZ levels in RDS' group after recovery, when compared to preterm controls. In RDS, no significant correlations existed between PTZ levels (before and after recovery) and routine investigations except for a significant negative correlation with platelets count. No significant differences were found in PTC levels between the 3 studied groups. To conclude: premature newborns suffering from RDS showed decreased serum protein Z levels than normal preterm control newborns with further increase in its pattern after recovery. Further studies are recommended to evaluate the role of PTZ on outcome in premature newborns with RDS and to evaluate the relationship between protein PTZ and PTC and other coagulation factors incriminated in the development of RDS.

Stenotrophomonas maltophilia infection of the central venous catheter and lysis of an old thrombosis in a post-bone marrow transplantation child: Implications in the fibrinolytic process

In this report, we describe an 11-y-old girl who developed jugular venous thrombosis after allogeneic bone marrow transplantation for lymphoma and then experienced dissolution of the thrombosis following catheter-related Stenothrophomonas maltophilia bactearemia. The lysis of the old thrombosis around the central venous catheter suggested a local fibrinolytic activity of S. maltophilia. The global fibrinolytic capacity (GFC) was also tested in vitro by using S. maltophilia cultures obtained from the present patient; GFC of the patient was compared to that of another isolate of S. maltophilia, other bacteria (S. pyogenes and E. coli), and control plasma. The fibrinolytic capasity of S. maltophilia was significantly higher than that of the control plasma (p<0.05) and almost equal to that of S. pyogenes (p>0.05). Thus, if a potent local fibrinolytic activity of S. maltophilia is evident, the use of the fibrinolytic enzyme of S. maltophilia as a thrombolytic agent may be a useful therapeutic adjunct in the future. Further studies are needed to comfirm the results obtained in the present study.

Thrombin activatable fibrinolysis inhibitor activity, thrombin-antithrombin complex and D-dimer levels in preterm neonates with early respiratory distress syndrome

Intraalveolar fibrin deposition found in neonates with respiratory distress syndrome (RDS) is explained by the activation of the coagulation system and inefficient fibrinolysis. However, thrombin activatable fibrinolysis inhibitor activity (TAFIa), an inhibitor of fibrinolysis, and the ratio of D-dimer to thrombin-antithrombin complex (D-dimer/TAT), an index of fibrinolytic activity, have not been reported previously in neonatal RDS. Aim of this study is to evaluate the influence of plasma TAFIa levels on the fibrinolytic state in neonatal RDS. The RDS group (Group 1) consisted of 29 neonates, and 18 neonates served as the control group (Group 2). Plasma TAFIa levels and D-dimer/TAT ratios were evaluated in all neonates in the first 6 hr of life. Neonates in the RDS group were further divided into two subgroups; Group 1a consisted of 12 neonates with evidence of mild asphyxia (Apgar score at 5 min <7 and cord pH <7.26), and Group 1b consisted of 17 nonasphyxiated neonates. No significant difference was found in TAFIa levels and D-dimer/TAT ratios between Groups 1 and 2 [214% (56.2-361%) and 124.3 (4.4-3,921) in Group 1 and 201% (60.3-381%) and 147 (5.9-1,426) in Group 2]. There were negative correlations between cord pH and TAFIa levels in both groups. Increased TAFIa levels and decreased D-dimer/TAT ratios and platelet counts were detected in mildly asphyxiated neonates when compared with nonasphyxiated ones. TAFIa is not responsible for the hypofibrinolytic state reported in RDS. However, asphyxia influences TAFIa levels and increased TAFIa levels depress fibrinolysis.

Unchanged global fibrinolytic capacity during the course of hematopoietic stem cell transplantation

Hemostatic changes due to vascular endothelial damage are seen during the course of hematopoietic stem cell transplantation (HSCT). The fibrinolytic response to ongoing hemostatic activation in HSCT remains to be elucidated. Global fibrinolytic capacity (GFC) is a novel method, which reflects the amount of generated D-dimer when fibrinolysis of a freeze-dried fibrin clot is stopped by introducing aprotinin. GFC is sensitive to all the factors involved in the process of fibrinolysis. The aim of this study was to serially assess GFC at certain critical time points (days -1, +7, +14, +21 prior to and following stem cell infusion) during the course of HSCT. The study group comprised 16 patients with hematological malignancies (11 women, five men; median age 32+/-9 years) in whom HSCT had been performed. Thirty healthy adults (21 women, nine men; median age 31+/-7 years) served as controls. In this study, global fibrinolytic response, as reflected by GFC, was unchanged despite ongoing hemostatic activation, as indicated by D-dimer, moreover GFC remained stable, despite the development of thrombocytopenia associated with HSCT prior to platelet engraftment. Our results indicate that a global fibrinolytic response was impaired as a compensatory response to endothelial activation and to other hemostatic changes seen in HSCT. Further studies in larger HSCT populations are warranted to better understand the implications of these findings.

Global fibrinolytic capacity in children on dialysis

Disturbances of coagulation and fibrinolysis have been reported in patients with chronic uremia. Studies of different coagulation and fibrinolysis parameters in regularly dialyzed patients have yielded conflicting results. Global fibrinolytic capacity (GFC) examines the function of the entire fibrinolytic system. This assay is a sensitive and reliable method for evaluating the fibrinolytic function of plasma in vitro. In this study, GFC was used as a screening test to investigate the effects of two different dialysis modalities on the fibrinolytic system on children on long-term dialysis.

MATERIALS AND METHODS

The study included 12 children (age range, 11-20 years; mean age, 15.9+/-3.3 years) who were undergoing regular hemodialysis (HD) and 12 children (age range, 10-15 years; mean age, 13.1+/-1.7 years) who were undergoing continuous ambulatory peritoneal dialysis (CAPD). Thirteen healthy age- and sex-matched subjects served as controls. Each sample was investigated for complete blood count and serum levels of C-reactive protein, serum electrolytes, total cholesterol, triglyceride, fibrinogen, total protein and albumin. A GFC assay was also done in each case.

RESULTS

The mean GFC in the CAPD group was lower than that in the HD and control groups (p<0.05). There was no significant difference between the mean GFC values of HD patients and controls. The mean serum albumin level was lower in CAPD patients than in HD patients (p<0.05), and there was also a positive correlation between serum albumin level and GFC in patient groups(r=0.52, p<0.05). Global fibrinolytic capacity was positively correlated with hemoglobin level and negatively correlated with weekly erythropoietin dose per kg body weight (r=0.56 and r=-0.49, respectively; p<0.05).

CONCLUSION

The results suggest that CAPD patients have decreased fibrinolytic capacity compared to HD patients. Hypoalbuminemia and erythropoietin treatment may contribute to suppression of fibrinolytic function CAPD patients.

The Effects of Atorvastatin Treatment on the Fibrinolytic System in Dyslipidemic Patients

Statins have pleiotrophic effects related to the pathogenesis of atherosclerosis and thrombogenicity of the vessel wall beyond lipid lowering. The aim of the present study was to examine the effect of atorvastatin treatment on the fibrinolytic system in patients with dyslipidemia. The investigation was carried out on 41 dyslipidemic patients (21 males and 20 females) with a mean age of 53.8 years (range, 30-76). The patients were divided into subgroups according to their cholesterol and triglyceride levels as hypercholesterolemic (n = 26) and mixed-type hyperlipidemic (n = 15) and their risk factors for coronary heart disease including age, sex, hypertension, obesity, smoking, and family history. The patients were started on atorvastatin 10 mg/day, and evaluated within 6-12 weeks to assess the changes in fibrinolytic parameters including global fibrinolytic capacity, plasminogen activator inhibitor type-1 and tissue plasminogen activator, and lipids. After successful lipid-lowering therapy, global fibrinolytic capacity (P = 0.003) and tissue plasminogen activator levels (P = 0.04) were found to be increased and plasminogen activator inhibitor type-1 levels (P = 0.02) decreased in dyslipidemic patients. Global fibrinolytic capacity levels increased (P < 0.001) and plasminogen activator inhibitor type-1 levels decreased (P = 0.01) in patients with hypercholesterolemia (n = 26). However, no significant changes were observed in fibrinolytic parameters in patients with mixed-type hyperlipidemia (n = 15). When the patients were separately evaluated according to risk factors, significant beneficial effects on the fibrinolytic system were observed, especially in patients without obesity and hypertension as well as in older patients and males. These findings suggest that atorvastatin treatment has a beneficial effect on the fibrinolytic system in patients with hypercholesterolemia, but not in patients with mixed-type hyperlipidemia. Further studies are needed to show whether higher doses and longer periods of lipid lowering treatment have beneficial effects in patients with mixed type hyperlipidemia and some risk factors.