Changes in plasma endocan level are related to circulatory but not respiratory failure in critically ill patients with COVID-19.

The aim of this prospective, observational study was to assess whether changes in the level of endocan, a marker of endothelial damage, may be an indicator of clinical deterioration and mortality in critically ill COVID-19 patients. Endocan and clinical parameters were evaluated in 40 patients with acute respiratory failure on days 1-5 after admission to the intensive care unit. Endocan levels were not related to the degree of respiratory failure, but to the presence of cardiovascular failure. In patients with cardiovascular failure, the level of endocan increased over the first 5 days (1.63, 2.50, 2.68, 2.77, 3.31 ng/mL, p = 0.016), while in patients without failure it decreased (1.51, 1.50, 1.56, 1.42, 1.13 ng/mL, p = 0.046). In addition, mortality was more than twice as high in patients with acute cardiovascular failure compared to those without failure (68% vs. 32%, p = 0.035). Baseline endocan levels were lower in viral than in bacterial infections (1.57 ng/mL vs. 5.25 ng/mL, p < 0.001), with a good discrimination between infections of different etiologies (AUC of 0.914, p < 0.001). In conclusion, endocan levels are associated with the occurrence of cardiovascular failure in COVID-19 and depend on the etiology of the infection, with higher values for bacterial than for viral sepsis.

Citrulline, Intestinal Fatty Acid-Binding Protein and the Acute Gastrointestinal Injury Score as Predictors of Gastrointestinal Failure in Patients with Sepsis and Septic Shock.

Gastrointestinal (GI) failure can be both a cause of sepsis and a consequence of the systemic pro-inflammatory response in sepsis. Changes in biomarkers of enterocyte damage, citrulline and I-FABP (intestinal fatty acid binding protein), may indicate altered intestinal permeability and damage. The study group consisted of patients with sepsis (N = 28) and septic shock (N = 30); the control group included patients without infection (N = 10). Blood samples were collected for citrulline and I-FABP and a 4-point AGI score (acute GI injury score) was calculated to monitor GI function on days 1, 3, 5, 7, and 10. Citrulline concentrations in the study group were lower than in the control. Lower values were also noted in septic patients with shock when compared to the non-shock group throughout the study period. I-FABP was higher in the septic shock group than in the sepsis group only on days 1 and 3. Citrulline was lower in patients with GI failure (AGI III) when compared to AGI I/II, reaching significance on days 7 (p = 0.034) and 10 (p = 0.015); moreover, a higher AGI score was associated with an increased 28 day mortality (p = 0.038). The results indicate that citrulline measurements, along with the AGI assessment, have clinical potential in monitoring GI function and integrity in sepsis.

Intestinal Fatty Acid Binding Protein (I-FABP) as a Prognostic Marker in Critically Ill COVID-19 Patients.

Gastrointestinal symptoms are common in critically ill COVID-19 patients. There is currently no generally recognized method of assessing gastrointestinal injury in unconscious or sedated intensive care unit (ICU) patients. I-FABP (intestinal fatty acid binding protein) and citrulline have previously been studied as potential biomarkers of enterocyte damage in various gastrointestinal tract diseases, and changes in the levels of these markers may reflect intestinal wall damage in COVID-19. Patients with critical COVID-19, with diagnosed sepsis, or septic shock requiring ICU treatment were included in the study. Blood samples for citrulline and I-FABP were taken daily from day 1 to 5. I-FABP levels were significantly higher in patients who eventually died from COVID-19 than in survivors, and the optimal I-FABP cut-off point for predicting 28-day mortality was 668.57 pg/mL (sensitivity 0.739, specificity 0.765). Plasma levels of I-FABP, but not citrulline, were associated with significantly higher mortality and appeared to be a predictor of poor outcome in multivariate logistic regression analysis. In conclusion, I-FABP seems to be an effective prognostic marker in critically ill COVID-19 patients. Assessing mortality risk based on intestinal markers may be helpful in making clinical decisions regarding the management of intestinal injury, imaging diagnostics, and potential surgical interventions.

Explainable Artificial Intelligence Helps in Understanding the Effect of Fibronectin on Survival of Sepsis.

Fibronectin (FN) plays an essential role in the host's response to infection. In previous studies, a significant decrease in the FN level was observed in sepsis; however, it has not been clearly elucidated how this parameter affects the patient's survival. To better understand the relationship between FN and survival, we utilized innovative approaches from the field of explainable machine learning, including local explanations (Break Down, Shapley Additive Values, Ceteris Paribus), to understand the contribution of FN to predicting individual patient survival. The methodology provides new opportunities to personalize informative predictions for patients. The results showed that the most important indicators for predicting survival in sepsis were INR, FN, age, and the APACHE II score. ROC curve analysis showed that the model's successful classification rate was 0.92, its sensitivity was 0.92, its positive predictive value was 0.76, and its accuracy was 0.79. To illustrate these possibilities, we have developed and shared a web-based risk calculator for exploring individual patient risk. The web application can be continuously updated with new data in order to further improve the model.

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.

Plasma and Cellular Forms of Fibronectin as Prognostic Markers in Sepsis.

BACKGROUND: There is a pressing need for specific prognostic markers that could be used to monitor the severity of sepsis. The aims of our study were to investigate changes in the expression of different molecular forms of fibronectin in sepsis and to assess their relationship to the clinical severity and mortality of patients. Material and Methods. Forms of fibronectin: plasma (pFN), cellular (EDA-FN), FN-fibrin complexes, and fibronectin fragments were analyzed in 71 sepsis patients (survivors and nonsurvivors) and in the control by ELISA and immunoblotting. RESULTS: The baseline pFN concentration of patients with sepsis was significantly lower than in the control (133.0 mg/L vs. 231.2 mg/L) (P < 0.001), and in nonsurvivors, it was lower than in survivors (106.0 mg/L vs. 152.8 mg/L) (P = 0.004). The baseline EDA-FN was significantly elevated in both sepsis groups (survivors: 6.7 mg/L; nonsurvivors: 9.4 mg/L) compared to the control (1.4 mg/L) (P < 0.001). It should be noted that among patients with more severe sepsis, the EDA-FN level was higher in nonsurvivors than in survivors. Furthermore, molecular FN-fibrin complexes as well as FN fragments occurred much more frequently in nonsurvivors than in survivors. CONCLUSION: The study showed that in sepsis, changes in plasmatic and cellular form of fibronectin were associated with the severity of sepsis and may be useful predictors of outcome.

Fibronectin and its soluble EDA-FN isoform as biomarkers for inflammation and sepsis.

Fibronectin (FN) is a widely distributed glycoprotein which is present in different bodily fluids, on the surface of cells and in the extracellular matrix (ECM). It plays roles in various processes, including cell adhesion, migration, growth, proliferation, and tissue repair. Fibronectin exists in 2 forms: a soluble, inactive molecule, called plasma FN (pFN), which is synthesized by hepatocytes in the liver, and an insoluble cellular form (cFN), which is produced locally by different types of cells and is a key component of the ECM. Fibrinogen fibrils ensure structural support for cell adhesion and promote cell migration, proliferation and apoptosis. Additionally, FN controls the availability of growth factors. The plasma form of FN is a crucial component of the fibrin clot in the early wound-healing response, while the cellular form of FN supports efficient platelet adhesion, activation, aggregation, and procoagulant activity. Alternative splicing of the FN gene results in the generation of protein variants which contain the additional isoforms - extra domain A of FN (EDA) and extra domain A of FN (EDB); these are associated with, e.g., tissue remodeling, fibroblast differentiation, inflammation, and tumor progression. Fibronectin also serves as a target for a large number of bacterial proteins, and as part of a 3-component bridge (FN, integrin and FN-binding proteins - FnBPs) it contributes to bacterial colonization of endothelial and epithelial cells. Fibronectin has been identified in sepsis in humans as a negative acute-phase protein, and a low level of FN seems to be a marker of a poor prognosis for a patient. Here, the role of FN in inflammatory processes and sepsis is presented.

Potential plasma biomarkers of bladder cancer identified by proteomic analysis: A pilot study.

BACKGROUND: Bladder cancer diagnosis and surveillance includes cystoscopy and cytology. New methods for the detection of bladder cancer are needed, because cystoscopy is invasive and expensive, and because urine cytology is not sensitive enough. OBJECTIVES: The aim of the study was to select potential plasma protein markers for bladder cancer which could be useful in developing a specific laboratory test to improve diagnosis and to establish treatment strategies in order to prevent the recurrence of the disease. MATERIAL AND METHODS: Plasma proteome maps were prepared based on 2-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), combined with image gel analysis and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry of plasma samples from patients with urothelial bladder cancer, and they were compared to normal samples. RESULTS: The analyses of bladder cancer plasma samples allowed us to distinguish 3 groups of proteins whose relative abundance differed from that in normal samples. The 1st one comprised modified forms of plasma transferrin, fibrinogen gamma and complement C3b, which were absent in normal plasma. The 2nd group comprised haptoglobin, alpha-2-macroglobulin, vitamin D-binding protein, and pigment epithelium-derived factor, which occurred in the cancerous samples in large quantities. The 3rd group consisted of 3 molecular forms of immunoglobulin M (IgM), the relative abundance of which was significantly lower in the cancerous plasma samples. CONCLUSIONS: The data indicated potential plasma biomarkers associated with inflammation, immunity and coagulation processes accompanying bladder cancer. They could be used for the development of a laboratory test(s) useful in clinical practice.

Preoperative blood morphology and incidence of acute kidney injury after on-pump coronary artery bypass grafting - a single-center preliminary report.

INTRODUCTION: Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) performed in cardiopulmonary bypass (CPB) may complicate the postoperative course and has a negative impact on outcome. In some cases, postoperative AKI develops in spite of normal baseline creatinine concentration and estimated glomerular filtration rate (eGFR). AIM: To examine whether there is any association between the preoperative blood morphology and incidence of post-operative AKI. MATERIAL AND METHODS: The study involved 62 consecutive patients with the mean age of 64.0 ±7.4 years who underwent CABG in CPB. Before surgery, blood morphology and biochemistry were analyzed. Patients with eGFR below 60 ml/min/1.73 m2 were excluded. After the operation, parameters of renal function were checked systematically. Acute kidney injury was defined according to the Acute Kidney Injury Network (AKIN) classification. RESULTS: Twenty-one (33.9%) patients presented AKI (group AKI), although in the majority of them (n = 16) it was temporary and medical management was enough to cure AKI. Only in 1 (1.6%) case was renal replacement therapy necessary. In group AKI, patients' preoperative hemoglobin concentration (8.46 ±0.72 mM/l), red blood cell count (4.51 ±0.39 × 1012/l) and hematocrit (0.40 ±0.04) were significantly lower (p < 0.05) than in group C (9.07 ±0.57 mM/l; 4.78 ±0.36 × 1012/l; 0.43 ±0.03, respectively). Interestingly, the baseline parameters of renal function were comparable between groups. CONCLUSIONS: Hemoglobin concentration and red blood cell counts close to the lower limit of the normal range may enable identification of patients at risk of AKI early after CABG in CPB among individuals with normal preoperative biochemical parameters of renal function.

Clinical presentation, surgical management, and outcomes of patients treated for aortic stenosis and coronary artery disease. Does age matter?

BACKGROUND: Aortic stenosis and coronary artery disease (CAD) sharing similar risk factors are associated with aging of the human population. AIM: The purpose of this study was to examine whether age affects clinical presentation, intraoperative management, and outcomes of patients who undergo simultaneous operations of aortic valve replacement (AVR) and coronary artery bypass grafting (CABG). METHODS: The study involved 452 consecutive patients aged 64.8 ± 8.2 years (range 38-79 years), who underwent combined AVR and CABG between 2005 and 2015. They were divided into three groups: Y (young; below the first quartile; n = 114), M (middle-aged; 58-71 years; n = 225) and E (elderly; above the third quartile; n = 113). Pre- and intraoperative variables were analysed. The deaths that occurred in hospital and throughout follow-up were defined as cardiac- or non-cardiac-related. The probability of survival was calculated with the use of Kaplan-Meier curves. RESULTS: Coronary artery disease was more extensive in group E than in group Y (p < 0.05). Complete myocardial revasculari-sation was performed in 94.1%, 76.2%, and 62.8% in groups Y, M, and E, respectively (p < 0.05). In-hospital mortality was 2.0%, 5.3%, and 6.4%, in groups Y, M, and E, respectively. Early morbidity was significantly higher in group E than in groups M or Y. The 12- and 60-month freedom from cardiac-related death was higher in group Y (0.98 ± 0.02 and 0.94 ± 0.03) than in group E (0.93 ± 0.02 and 0.85 ± 0.03; p = 0.023, respectively). Left ventricular ejection fraction below 0.4 and incomplete revascularisation were associated with worse prognosis, particularly in group E. CONCLUSIONS: Elderly patients undergoing combined procedures of AVR and CABG having more extensive CAD less often receive complete revascularisation, are at higher risk of early organ failure, and present markedly reduced rates of freedom from cardiac-related deaths throughout follow-up than younger subjects.

Potentially positive ageing-related variations of medial smooth muscle cells in the saphenous veins used as aortocoronary bypass grafts.

INTRODUCTION: Currently, elderly people constitute a large proportion of patients undergoing coronary artery bypass grafting (CABG). Activated smooth muscle cells in the tunica media of saphenous vein (SV) grafts are thought to play a key role in the formation of neointima and development of occluding atherosclerotic plaques. The aim of this study was to identify ageing-related variations in the expression of the smooth muscle cells pro-teins that may impact on patency rate of the grafts and the CABG outcomes. MATERIAL AND METHODS: The study involved 216 consecutive patients with the mean of 62.7 ± 8.4 years who underwent isolated CABG with at least one SV aortocoronary bypass graft. Expression of a-smooth muscle actin (a-SM actin), smooth muscle-myosin heavy chain (SM-MHC), calponin (CALP), cytokeratin 8 (CK-8), metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinases-2 and -3 (TIMP-2, TIMP-3) in the SV wall was assessed by immunohistochemistry and correlated with the age of patients. RESULTS: Calponin and a-SM actin were expressed in all studied SV transplants. SM-MHC immunoreactivity was observed in SV segments in 68.5% of patients, whereas MMP-2a and TIMPs expression was found in 75% of cases. In more than 50% of analyzed SV transplants, no expression of cytokeratin-8 was found. Moderate correlations between preexisting expressions of either cytoskeletal or hemostatic proteins in the tunica media of the SV grafts and the age of CABG patients were demonstrated. They were positive for SM-MHC (r = 0.494), CALP (r = 0.548), TIMP-2 (r = 0.413) and TIMP-3 (r = 0.406) whereas negative for CK-8 (r = -0.528) and MMP-2 (r = -0.417). CONCLUSIONS: Age-dependent decreases in the expression of MMP-2 and CK-8 accompanied by increases in expression of SM-MHC, TIMP-2 and TIMP-3 may promote SV graft patency and, thus, suggest a rationale for common use of SV grafts in the elderly.

Routine transfusion of platelet concentrates effectively reduces reoperation rate for bleeding and pericardial effusion after elective operations for ascending aortic aneurysm.

Patients with ascending aortic aneurysm undergoing complex surgical procedures are at increased risk of early postoperative excessive blood loss. The aim of this study was to analyze safety and efficacy of routine transfusions of platelet (PLT) concentrates in reduction of hemorrhagic postoperative complications. The study involved 396 consecutive patients (289 males and 107 females) with the mean age of 55.9 ± 13.6 years who underwent elective operations for aortic aneurysms. They were divided retrospectively into two groups, without (group A; n = 123) or with the routine use of PLTs (group B; n = 273). PLTs were transfused intraoperatively just after completion of cardiopulmonary bypass. Twelve patients in group A (9.8%) and 10 (3.7%) in group B required re-thoracotomy due to hemorrhage (p = 0.027). Routine transfusions of PLT concentrates reduced postoperative incidence of excessive pericardial effusion from 24.1% in group A to 2.1% in group B (p = 0.002). In a consequence, significantly less units (p < 0.0001) of red blood concentrates and fresh frozen plasma were transfused in group B than in group A. The rates of other adverse events in the early postoperative period did not differ between groups. Patients with pericardial effusion required 6.3 ± 2.7 additional days of hospitalization due to surgical re-intervention. Neither blood transfusion-related infections nor adverse reactions were noted. In conclusion, routine intraoperative transfusions of PLT concentrates in patients with ascending aortic aneurysms significantly reduced a need for re-intervention due to both early bleeding and late cardiac tamponade.

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.

Occurrence of fibronectin-fibrin complexes in plasma of patients with multimorbidity due to the inflamm-aging phenomenon.

BACKGROUND: Multimorbidity is the co-occurrence of chronic diseases associated with low-grade chronic inflammation of connective tissue. AIM OF STUDY: Frequency of occurrence and relative amounts of fibronectin (FN) complexes with fibrin (FN-fibrin) and FN monomer were analyzed in 130 plasma samples of 18 to 94-year-old multimorbid patients in relation to concentrations of FN and extra domain A (EDA)-FN, and C-reactive protein (CRP) as well as to age, number of coexisting chronic diseases and presence of specified diseases. RESULTS: Immunoblotting revealed, besides FN dimer, the presence of FN monomer, and 750-, 1000-, and 1300-kDa FN-fibrin complexes in the multimorbid plasmas. The FN-fibrin complexes appeared more frequently and in higher relative amounts, but FN monomer less frequently and in a lower relative amount in the groups of elderly multimorbid patients, with a higher number of coexisting diseases and with dominance of cardiovascular diseases and osteoarthrosis, and with CRP concentration of 3-5mg/l. In contrast, the normal plasma contained only the FN-fibrin complex of 750 kDa in a lower relative amount, but with an increasing amount with normal aging. Moreover, FN concentration increased and EDA-FN decreased with the number of co-existing diseases and aging of patients, although both concentration values were lower than in the age-matched normal groups. FN concentration was the lowest in the exacerbation of a chronic disease and EDA-FN in the stable chronic disease groups. CONCLUSION: The alterations in plasma FN molecular status were associated with micro-inflammation and micro-coagulation, as well as multimorbidity of subjects and their physiological aging.

Occurrence of soluble supra-molecular FN-fibrin complexes in the plasma of children with recurrent respiratory infection.

OBJECTIVES: Fibronectin (FN) is able to bind fibrin and FN-fibrin complexes and is found in the plasma of some patients suffering from inflammatory disease. The present study was undertaken to determine whether soluble supra-molecular FN-fibrin complexes were present in the plasma of children with recurrent respiratory infections (RRI). DESIGN AND METHODS: The frequency of occurrence and relative amounts of the supra-molecular FN-fibrin forms, concentrations of immunoglobulins and numbers of natural killer cells (NK) were determined in the plasma of children with recurrent respiratory infections. The frequencies of these parameters were compared with their frequencies in the plasma of children with acute respiratory infections and plasma from healthy children. RESULTS: SDS-agarose immunoblotting of patients' plasma revealed the presence of several additional FN-fibrin bands, with decreasing electrophoretic mobilities and increasing molecular masses of 750 kDa, 1000 kDa, 1300 kDa, 1600 kDa and 1900 kDa. Such FN-fibrin complexes occurred with higher frequency and in larger amounts in the plasma of children with RRI and acute infection than they did in plasma from normal children. Moreover, bands above 1000 kDa were absent in most young healthy individuals. The occurrence of FN-fibrin complexes did not correlate with either immunoglobulin concentrations, or with the number of NK cells. CONCLUSIONS: The occurrence of plasma supra-molecular FN-fibrin complexes is associated with acute and recurrent respiratory infections of children.

Identification of soluble supramolecular FN-fibrin complexes in human plasma.

SDS-agarose FN immunoblotting of 257 normal and pathological human plasma samples revealed the ladder pattern of multiple plasma FN bands which corresponded to FN monomer and dimer, and 5 FN-fibrin bands with increasing molecular masses. The FN-fibrin bands of about 750 kDa, 1000 kDa, 1300 kDa, 1600 kDa, and 1900 kDa appeared more frequently and in significantly higher relative amounts in the pathological samples (P < 0.000) than in relatively healthy individuals. The revealing of high-molecular FN-fibrin complexes by SDS-agarose FN immunobloting might have the potential to become a laboratory biomarker of some diseases in which the coagulation system is triggered.

Preexisting high expression of matrix metalloproteinase-2 in tunica media of saphenous vein conduits is associated with unfavorable long-term outcomes after coronary artery bypass grafting.

INTRODUCTION: Migration of the smooth muscle cells (SMCs) to the tunica media in the saphenous vein (SV) transplants is facilitated by matrix metalloproteinases (MMPs). The aim of this study was to identify any associations between expression of MMP-2 or endogenous tissue inhibitors (TIMP-2 and TIMP-3) in the SV segments and late failure of the SV grafts. METHODS: Two hundred consecutive patients with a mean age of 63.1 ± 8.9 years who underwent primary isolated venous CABG were examined. Patients were retrospectively split into two subgroups, with the SV graft disease (SVGD (+); n = 47) or without it (SVGD (-); n = 153). In the SV segments, immunohistochemical analysis of the expression of the MMP-2, TIMP-2, and -3 was performed. RESULTS: In the SVGD (+) patients, tissue expression of MMP-2 was stronger, whereas that of both TIMPs was weaker than in the SVGD (-) patients. In majority of the SV segments obtained from the SVGD (-) individuals, a balance in MMP and TIMP expressions was found, whereas an upregulation of MMP-2 expression was usually noted in the SVGD (+) subjects. CONCLUSION: The strong expression of MMP-2 accompanied by reduced immunostaining of both TIMPs is associated with the development of the SV graft disease and unfavorable CABG outcomes.

Alterations in molecular status of plasma fibronectin associated with aging of normal human individuals.

OBJECTIVES: Senescence, progressive deterioration of many bodily functions might be associated with age-dependent alterations of plasma fibronectin (FN) molecular status (i.e., domain, glycotope, and molecular form expressions). DESIGN AND METHODS: FN molecular status was analyzed in 127 plasma samples of healthy individuals in groups of newborns, and subjects aged 3-14, 15-39, 41-59, and 60-82 years by FN-ELISA, lectin-FN-ELISA, and immunoblotting using a set of domain-specific monoclonal antibodies, specific lectins, and monoclonal antibody to FN, respectively. RESULTS: During the first four decades of human life the levels of cell-binding-, carboxyl-terminal-, collagen-, heparin-, and fibrin-domains of plasma FN gradually increased. In subjects aged up to 82 years the cell-binding and carboxyl-terminal FN domain concentrations did not change, while the heparin, fibrin, and collagen domains significantly increased. The relative reactivity of plasma FN with Maackia amurensis lectin, specific to α2,3-linked sialic acid, significantly decreased after birth, reaching a stable level in the subsequent life period, whereas with Sambucus nigra lectin, specific to α2,6-linked sialic acid, it significantly decreased in the 60-82 year old group. Moreover, the appearance of 280-kDa and 320-kDa FN bands, absent in young and mature healthy individuals, was found in the groups of 41-59 and 60-82 year olds. CONCLUSIONS: The alterations of FN molecular status throughout growth, maturation and senescence might be associated not only with disturbances in the balance of FN production rate and degradation, but concomitantly with conformational rearrangements of FN and its engagement in age-related vascular remodeling processes.

Human plasma and cerebrospinal fibronectins differ in the accessibility of the epitopes on the N-terminal domains.

Three monoclonal antibodies specific to the central cell-binding and the C- and N-terminal domains of fibronectin (FN) were used to test antigenic epitope accessibility on human plasma and cerebrospinal fibronectins. In the plasma group, the mean N-terminal FN domain immunoreactivity was about one fourth that of the cell-binding and C-terminal domains, whereas in cerebrospinal fluid they were nearly equal. In the presence of 0.5-6 M urea N-terminal domain immunoreactivity in the plasma increased 3-6-fold, but it decreased 0.7-3-fold in the cerebrospinal fluid. Analysis of fibronectin domain immunoreactivities of the cell-binding and N-terminal domains by a panel of specific monoclonal antibodies may reveal N-terminal fibronectin domain accessibility for reaction with biological partner ligand(s) and/or processes in which FN could be implicated. Such determinations may have important clinical implications.

Molecular status of plasma fibronectin as an additional biomarker for assessment of Alzheimer's dementia risk.

BACKGROUND: Aberrant angiogenesis and senescence of the cerebrovascular system could initiate neurovascular events leading to neurovascular disorders. Fibronectin (FN) exerts a strong angiogenic influence on endothelial cells in the central nervous system. METHODS: In the present study the expression of the plasma fibronectin molecular forms in an Alzheimer patient group, compared with vascular dementia and age-matched control groups was analyzed by immunoblotting. RESULTS: FN in the plasma of the elderly individuals with and without dementia exists as a mixture of heterogeneous molecules with increasing molecular masses. Apart from the wide approximately 240-kDa and approximately 220-kDa FN bands, normally present in plasma, the high molecular FN forms having approximately 280 kDa and approximately 320 kDa appeared in the plasma of the Alzheimer dementia group more frequently and at the higher amounts than in the vascular dementia and age-matched nondemented groups. CONCLUSIONS: The plasma FN molecular status seems to be a molecular additional biomarker for assessment of dementia risk.