Fibronectin as a Marker of Disease Severity in Critically Ill COVID-19 Patients

The SARS-CoV-2 virus alters the expression of genes for extracellular matrix proteins, including fibronectin. The aim of the study was to establish the relationship between different forms of fibronectin, such as plasma (pFN), cellular (EDA-FN), and proteolytic FN-fragments, and disease severity and mortality of critically ill patients treated in the intensive care unit. The levels of pFN, EDA-FN, and FN-fragments were measured in patients with a viral (N = 43, COVID-19) or bacterial (N = 41, sepsis) infection, using immunoblotting and ELISA. The level of EDA-FN, but not pFN, was related to the treatment outcome and was significantly higher in COVID-19 Non-survivors than in Survivors. Furthermore, EDA-FN levels correlated with APACHE II and SOFA scores. FN-fragments were detected in 95% of COVID-19 samples and the amount was significantly higher in Non-survivors than in Survivors. Interestingly, FN-fragments were present in only 56% of samples from patients with bacterial sepsis, with no significant differences between Non-survivors and Survivors. The new knowledge gained from our research will help to understand the differences in immune response depending on the etiology of the infection. Fibronectin is a potential biomarker that can be used in clinical settings to monitor the condition of COVID-19 patients and predict treatment outcomes.

Fibronectin Molecular Status in Plasma of Women with Endometriosis and Fertility Disorders

The diagnosis of endometriosis and fertility disorders is difficult; therefore, it is necessary to look for reliable biomarkers. Analysis of the molecular status of fibronectin as a key player in repair and wound healing processes, as well as in coagulation and fibrinolysis pathways, is justified. ELISA and SDS-agarose immunoblotting were applied to determine the fibronectin concentration and presence and occurrence of soluble FN-fibrin complexes in the blood plasma of women with endometriosis (n = 38), fertility disorders (n = 28) and the healthy group (n = 25). The concentration of fibronectin in the blood plasma of women with endometriosis (292.61 ± 96.17 mg/L) and fertility disorders (287.53 ± 122.68 mg/L) was significantly higher than in the normal group (226.55 ± 91.98 mg/L). The presence of FN-fibrin complexes of 750, 1000, 1300, 1600 and 1900 kDa in the plasma of women with endometriosis and fertility disorders was shown. The presence of FN-fibrin complexes with a molecular mass of more than 1300 kDa in women with endometriosis and infertility and the complete absence of these complexes in healthy women may indicate an increased and chronic activation of coagulation mechanisms in these patients. The presence of complexes of high molecular mass may be one of the biomarkers of fertility disorders in women.

Role of Infection and Immunity in Bovine Perinatal Mortality: Part 2. Fetomaternal Response to Infection and Novel Diagnostic Perspectives

Simple Summary

Bovine perinatal mortality (death of the fetus or calf before, during, or within 48 h of calving at full term (≥260 days) may be caused by noninfectious and infectious causes. Although infectious causes of fetal mortality are diagnosed less frequently, infection in utero may also compromise the development of the fetus without causing death. This review presents fetomaternal responses to infection and the changes which can be observed in such cases. Response to infection, especially the concentration of immunoglobulins and some acute-phase proteins, may be used for diagnostic purposes. Some changes in internal organs may also be used as an indicator of infection in utero. However, in all cases (except pathogen-specific antibody response) non-pathogen-specific responses do not aid in pathogen-specific diagnosis of the cause of calf death. But, nonspecific markers of in utero infection may allow us to assign the cause of fetal mortality to infection and thus increase our overall diagnosis rate, particularly in cases of the “unexplained stillbirth”.

Abstract

Bovine perinatal mortality due to infection may result either from the direct effects of intrauterine infection and/or the fetal response to such infection, leading to the fetal inflammatory response syndrome (FIRS). Both intrauterine infection and FIRS, which causes multi-organ damage and involution of immune organs, compromise fetal survivability, sometimes fatally. Organ injury associated with FIRS may, in addition to causing fetal mortality, irreversibly compromise extrauterine adaptation of the neonate, a recognized problem in human fetuses. Diagnosis of intrauterine infection and of FIRS requires related, but independent analytical approaches. In addition to detection of pathogens, the immune and inflammatory responses of the bovine fetus may be utilized to diagnose intrauterine infection. This can be done by detection of specific changes in internal organs and the measurement of antibodies and/or elements of the acute phase reaction. Currently our ability to diagnose FIRS in bovine fetuses and neonates is limited to research studies. This review focuses on both the fetomaternal response to infection and diagnostic methods which rely on the response of the fetus to infection and inflammatory changes, as well other methods which may improve diagnosis of intrauterine infection in cases of bovine perinatal mortality.

Data Mining and Systematic Pharmacology to Reveal the Mechanisms of Traditional Chinese Medicine in Recurrent Respiratory Tract Infections' Treatment

Traditional Chinese medicine (TCM) was widely used in the treatment of recurrent respiratory tract infections (RRTIs) in East Asia, but its mechanism was not clear because of its complex prescription rules. This research prospectively collected 100 prescriptions of RRTI children treated with TCM. The characteristics of TCM in prescriptions were described and analyzed, and the rules of prescriptions were analyzed by hierarchical clustering and association rules. The results showed that the principle of RRTI was to pay equal attention to cold and mild, and six new meaningful prescriptions were obtained. Among them, the new prescription composed of Astragali Radix (Huangqi), Atractylodis Macrocephalae Rhizoma (Baizhu), Saposhnikoviae Radix (Fangfeng), Angelicae Sinensis Radix (Danggui), and Paeoniae Radix Rubra (Chishao) was an important method to treat RRTI. In order to explore the mechanism of the new prescription, the research obtained the action target of each herb of the core prescription on Integrative Pharmacology-based Research Platform of Traditional Chinese Medicine, TCMIP v2.0. The target genes were enriched by Metascape, and 93 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were obtained. According to the classification and statistics of KEGG type, it was found that the new prescription mainly intervened in the metabolic pathway dominated by amino acid metabolism. In addition, there were also many interventions in the nervous system-, endocrine system-, and digestive system-related pathways. This study summarized the prescription rule of TCM in the treatment of RRTI, analyzed the mechanism of supplementing deficiency, and provided a new idea for the treatment of RRTI.

Changes of plasma fibronectin and fibronectin-fibrin complexes in dams of stillborn dairy calves

Background

Fibronectin (FN) is a large (450–500 kDa), multidomain and multifunctional glycoprotein existing in mammalian tissues. Some fibronectin (FN) molecular forms might be involved in biological processes occurring within the perinatal period, such as tissue remodeling, coagulation, and repair.

Results

In this study fibronectin (FN) and fibrinogen (Fb) concentrations and FN-fibrin complexes occurrence and its relative amounts with increasing high molecular masses were respectively determined by ELISA, heat precipitation, and SDS-agarose-immunoblotting methods. Plasma samples from three groups of dams with: 1) singleton stillborn calf without or with negligible autolytic changes in internal organs (DSBn), 2) singleton stillborn calf with advanced autolytic changes in internal organs (DSBa), 3) singleton live-born control calf (DC), and 4) a group of cows during mid to late lactation (LC) were analyzed. Maternal plasma FN concentration in the DSBn and DSBa groups was significantly lower than in the LC group. The plasma samples of DSBa showed a significantly lower FN concentration than in the DC group. Plasma Fb concentration was significantly higher in the DSBa and DSBn, than in the LC group. FN immunoblotting of the cow plasma samples revealed, besides an FN-dimer band, the presence of supramolecular FN-fibrin bands corresponding to FN-fibrin complexes with increasing molecular masses: up to 5 bands from 750 kDa to 1900 kDa in the DSBn and DSBa plasma samples, two bands of 750 and 1000 kDa in the DC group, and only the smallest one of 750 kDa in the LC group.

Conclusions

The observed low FN concentration and occurrence of supramolecular FN-fibrin complexes (1000 kDa and more) in the maternal plasma comparing to cows in lactation might have been associated with periparturient changes in tissues. The presence in maternal plasma of high-molecular FN-fibrin complexes (1300–1900 kDa) arouse the question if this is the consequence of calf perinatal mortality.

Intestinal microbiota dysbiosis in children with recurrent respiratory tract infections

BACKGROUND

The impact of the gut microbiota on recurrent respiratory tract infection (RRTI) remains to be fully elucidated.

METHODS

To characterize the gut microbiota in patients with RRTI, fecal samples from 26 patients with RRTI and 23 healthy volunteers were profiled using the Illumina MiSeq platform. Beta diversity (Principal Component Analysis (PCA), Principal Co-ordinates Analysis (PCoA), Non-metric multidimensional scaling (NMDS)) analysis showed that the bacterial community structure segregated differently between the RRTI and control groups.

RESULTS

Results from alpha diversity analysis revealed lower microbiota diversity in samples from RRTI patients than in normal controls. Taxonomic analysis illustrated that the abundance of six phyla (Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, Tenericutes) and four genera (Enterococcus, Faecalibacterium, Bifidobacterium, Eubacterium were significantly different between these two groups. In addition, Enterococcus (P < 0.001) was more enriched in the RRTI group, whereas the abundances of Eubacterium (P < 0.001), Faecalibacterium (0.01 < P < 0.05) and Bifidobacterium (0.01 < P < 0.05) were reduced in the RRTI group compared to those in the normal control group. The performance of the model was assessed using ROC analysis, and Enterococcus, Eubacterium and Bifidobacterium achieved AUC values of 0.860, 0.820, and 0.689, respectively.

CONCLUSIONS

These results provide fundamental evidence in support of intestinal microbiota dysbiosis in children with RRTI.

Delivery-associated presence of supramolecular fibronectin-fibrin complexes in puerperal and cord plasma

Objective: The variable fibronectin (FN) molecular forms are known to be engaged in coagulation and fibrinolysis pathways as well as tissue remodeling and repair processes. Some of them seem to be indispensable molecules within intensive biological processes associated with delivery. The aim of the study was to evaluate the FN molecular status in maternal and cord plasma after vaginal birth and cesarean section (C-section). Materials and methods: The study included nonpregnant women's plasma samples (n = 31) and puerperal and cord plasma samples collected from 49 mothers who delivered healthy newborns at term by vaginal birth (n = 25) and C-section (n = 24). The maternal and cord plasma FN concentrations and presence and relative ratios of different FN-fibrin complexes were determined by ELISA and sodium dodecyl sulfate (SDS) -agarose immunoblotting, respectively. Results: FN concentration in puerperal plasma after vaginal birth (232.08 ± 71.8 mg/L) and C-section (228.17 ± 71.2 mg/L) was significantly higher than in the plasma of nonpregnant women (190.00 ± 48.75 mg/L). In contrast, FN concentration in cord plasma of the C-section group (101.95 ± 30.3 mg/L) was significantly lower than that of the vaginal birth group (121.80 ± 22.2 mg/L). Immunoblotting of puerperal and cord plasma distinguished the most abundant dimeric plasma FN form, the 220-280-kDa FN degradation products and 750-1900-kDa FN-fibrin complexes, which occurred more frequently and in higher amounts in puerperal and cord plasma groups than the nonpregnant women group, although independently of the mode of delivery. Conclusions: Occurrence and relative amount of delivery-associated FN-fibrin complexes in both puerperal and cord plasmas might be bound with the physiological adaptive mechanisms reducing the risk of hemorrhage and intensive remodeling and repair processes after delivery.

Time-dependent changes in extra-domain A-fibronectin concentration and relative amounts of fibronectin-fibrin complexes in plasma of patients with peripheral arterial disease after endovascular revascularisation

Fibronectin (FN) may be involved in time- and stage-dependent and inter-related controlled processes of inflammation, coagulation, and wound healing accompanying peripheral arterial disease (PAD). In the present study, FN and FN-containing extra-domain A (EDA-FN), macromolecular FN-fibrin complexes, and FN monomer were analysed in the plasma of 142 PAD patients, including 37 patients with restenosis, for 37 months after revascularisation. FN concentration increased significantly in the plasma of PAD patients within 7 to 12 months after revascularisation, whereas the high concentration of EDA-FN was maintained up to 24 months, significantly higher in the group 7 to 12 months after revascularisation with recurrence of stenosis and lower in the PAD groups 1 to 3 months and 4 to 6 months after revascularisation with comorbid diabetes and ulceration, respectively. The relative amounts of FN-fibrin complexes up to 1600 kDa and FN monomer were significantly higher, within intervals of 4 to 24 months and 4 to 6 months after revascularisation, respectively. Moreover, the relative amounts of 750 to 1600 kDa FN-fibrin complexes within 13 to 24 months after revascularisation were higher in comparison with those in the group without restenosis. In conclusion, high levels of EDA-FN and FN-fibrin complexes could have potential diagnostic value in the management of PAD patients after revascularisation, predicting restenosis risk.

Analysis of Soluble Molecular Fibronectin-Fibrin Complexes and EDA-Fibronectin Concentration in Plasma of Patients with Atherosclerosis

Atherosclerosis, a chronic vascular disease, leads to molecular events bound with interplaying processes of inflammation and coagulation. In the present study, fibronectin (FN), FN containing extra domain A (EDA-FN), frequency of occurrence, and relative amounts of soluble plasma FN-fibrin complexes were analyzed in 80 plasma samples of patients suspected of coronary artery disease based on clinical evaluation and changes in arteries found by computed tomographic coronary angiography. The study showed that in the plasma of the patients’ group with high risk of coronary artery disease EDA-FN concentration was significantly higher (3.5 ± 2.5 mg/L; P < 0.025) and the molecular FN-fibrin complexes of 1000 kDa and higher occurred more often than in the groups of patients with mild risk of coronary artery disease and the normal age-matched. The increased level of EDA-FN and occurrence of FN-fibrin complexes could have a potential diagnostic value in the diagnosis and management of patients with coronary artery disease.