Components Of Fibrinolytic System Research Articles

COAGULATION AND ANTICOAGULATION PARAMETERS IN MULTIPLE SCLEROSIS PATIENTS WITH AND WITHOUT COVID-19

The aim. To investigate plasma levels of main coagulation and fibrinolytic factors in MS patients with and without COVID-19 history. Materials and methods. A total of 127 participants were enrolled in this study, including 97 MS patients and 30 healthy controls (HC). Patients with MS were divided into two groups: MS+Covid group (n=41) – patients with MS, who had a laboratory-verified diagnosis of COVID-19 in the past 3-6-month period and MS group (n=56) – patients with MS, who did not suffer from COVID-19 previously. Determination of plasma levels of prothrombin, plasminogen, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), protein C (PC), soluble thrombomodulin (TM) was performed by means of enzyme-linked immunosorbent assay. Spectrophotometric techniques were used to determine concentrations of fibrinogen, soluble fibrin monomeric complexes (SFMC) as well as plasminogen activity and inhibitory potential of α-2-antiplasmin. Results. The MS group was characterized by elevated levels of plasma prothrombin, fibrinogen, D-dimer, SFMC, soluble TM compared to HC, while PC concentration did not differ between MS and HC groups. Plasma plasminogen level as well as plasma level of the potential plasmin activity were significantly decreased in MS patients compared to HC group. The plasma tPA level was significantly reduced while plasma PAI-I level was significantly increased in MS patients compared to HC. Patients of MS group had an increased level of plasma α-2-antiplasmin activity compared with HC group. To note, most of studied parameters did not differ between two MS groups, except protein C, soluble thrombomodulin levels and plasma α-2-antiplasmin activity. Conclusions. The results of our study showed that MS patients have got altered hemostasis parameters; however, further study is necessary to find out the relationship between particular components of coagulation and fibrinolytic systems and pathophysiology of MS. Additionally, our findings demonstrated that a SARS-CoV-2 infection had a limited effect on hemostasis parameters in MS patients, causing changes in only a few parameters, including thrombomodulin and protein C levels as well as α-2-antiplasmin activity.

A study of fibrinolytic system components in donor groups depending on various titers of circulating anti-SARS-CoV-2 IgG in the bloodstream.

The fibrinolytic system plays an important role in controlling blood coagulation at each stage, from thrombin generation to fibrin clot cleavage. Currently, long-term multiorgan dysfunction post-coronavirus disease 2019 (COVID-19) may include coagulation disorders. Little information is available about the potential causes of post-COVID-19 coagulopathy, but one of them may be subpopulation IgG produced by the immune system against SARS-CoV-2. This article describes the changes in the main parameters of the fibrinolytic system in donors with various titers of anti-SARS-CoV-2 IgG, which is part of a complex study of the hemostasis system in these donor groups. We determined the most significant parameters of the fibrinolytic system, such as potential activity and amount of plasminogen and tissue plasminogen activator (tPA), amount of plasminogen activator inhibitor-1 (PAI-1), inhibitory potentials of α-2-antiplasmin, α-1-antitrypsin, α-2-macroglobulin in the blood plasma of donor groups. The obtained results represent the maximum and minimum values of measurement parameters among donor groups with titers of anti-SARS-CoV-2 IgG at least 10 ± 3 Index (S/C), and their statistical differences from the reference point [donor group with titer of anti-SARS-CoV-2 IgG 0 Index (S/C)]. We established the changes in fibrinolytic parameters depending on the titers of anti-SARS-CoV-2 IgG. One conclusion can be drawn from this: anti-SARS-CoV-2 IgG population may influence coagulation in the post-COVID-19 period. Further research in-vitro and in-vivo experimental models using selected and purified IgG may confirm our previous findings.

Changes in levels of urokinase receptor and other components of fibrinolytic system in brain tissues in urokinase gene-knockout mice with B16/F10 melanoma growing together with chronic neurogenic pain

Purpose of the study. An analysis of the changes in components of the urokinase system in the brain of urokinase gene-knockout mice (uPA-/-) with B16/F10 melanoma growing alone and together with chronic neurogenic pain (CNP).Materials and methods. The study included male and female C57BL/6-PlautmI.IBug-ThisPlau6FDhu/GFDhu mice (uPA-/-) (n = 48) and C57BL/6 mice (uPA+/+) (n = 80) with transplanted B16/F10 melanoma growing solitarily and together with CNP. Levels of the urokinase receptor (uPAR) and plasmin (PAP) and activity and levels of the PAI-I inhibitor were measured in the brain of animals by ELISA.Results. Levels of uPAR, PAI-I and PAP in the brain differed only in intact uPA-/- males, being on average 1.6 times higher (p < 0.05) than in uPA+/+ mice. Among animals with CNP, uPA-/- males showed increased PAI-I by 1.3 times (p < 0.05) and decreased PAP by 2.6 times (p < 0.05), while in uPA+/+ males, changes in PAI-I and PAP were opposite; in uPA-/- females, levels of all indicators increased by 1.6–2.1 times (p < 0.05), unlike uPA+/+ females. Among animals with melanoma only, changes in the levels of uPAR, PAI-I and PAP in the brain tissues in uPA-/- males differed from the group with CNP and from uPA+/+ males; in uPA+/+ females, levels of uPAR and PAP increased by 1.7 and 3.0 times (p < 0.05), and only PAP increased in uPA-/- females by 3.2 times (p < 0.05). Combination of CNP with melanoma in uPA-/- mice, regardless of their gender, down-regulated levels of uPAR and PAI-I on the average by 1.5 and 2.0 times, respectively (p < 0.05), and up-regulated PAP on the average by 2.2 times (p < 0.05) compared to the levels in animals with CNP; in uPA+/+ animals, similar decline of uPAR by 3.7 times (p < 0.05) was registered only in males, and an increase of PAI-I by 2.0 times (p < 0.05) was noted in all mice.Conclusion. Changes in the studied parameters in the brain tissue of urokinase gene-knockout animals in response to stress factors indicate the role of the brain urokinase system in the response to both CNP and melanoma growth, and the gender specificity of these changes may be another factor that conditions gender differences in the risk of occurrence and course of cutaneous melanoma.

He effects of NETosis on fibrinolysis in colon cancer patients

Aim. To investigate formation of neutrophil extracellular traps (NETs) and their impact on fibrinolysis in patients with colon cancer.Materials and methods. The study was performed in two groups. The experimental group consisted of patients with stage 2–3 non-metastatic colon cancer (n = 17, average age – 67 years). The control group included healthy volunteers matched by sex and age (n = 30, average age – 68 years). An experimental model was created from the whole blood. It included platelet-poor plasma and an isolated culture of neutrophils, previously induced to NETosis by adding 100 nmol PMA. The samples were incubated for 4 hours, then the test tubes were centrifuged to pellet cells and their remnants, and the plasma was transferred for subsequent examination. The plasma incubated with intact neutrophils was used as a control. The levels of interleukin-8 (IL-8) and P-selectin glycoprotein ligand-1 (PSGL-1) were used to determine the degree of cell activation. NETosis was confirmed by enzyme-linked immunosorbent assay (ELISA) and fluorescent microscopy. Fibrinolysis was assessed using the thrombodynamics test. The results were compared with the levels of fibrinolytic system components measured by flow cytometry.Results. In the control group, NETosis induction contributed to pronounced neutrophil activation that was accompanied by an increase in the IL-8, PSGL-1, and plasminogen levels, a decrease in PAI-1, and enhancement of fibrinolysis, compared with the intact samples. Higher levels of IL-8, PSGL-1, plasminogen, and PAI-1 and intensified fibrinolysis were detected in the intact samples. However, PMA-induced NETosis did not result in an increase in the degree of activation and significant changes in the given parameters.Conclusion. NETosis promotes both formation and lysis of fibrin clots. However, in cancer patients, suicidal NETosis does not contribute to fibrinolysis due to intracellular protease depletion, which may be one of the mechanisms causing hypercoagulation and insufficient fibrinolysis in cancer.

Abstract PO-127: A uPA/uPAR axis in both the tumor cell and stromal compartment drives PDAC disease progression

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a lethal solid tumor malignancy with a 5-year survival rate of 9%. In both patients and animal models of disease, PDAC is associated with robust coagulation system activity. Intriguingly, in addition to being a rich source of procoagulant factors, PDAC tumors highly express fibrinolytic system components. Supporting this concept, urokinase plasminogen activator (uPA) and uPA receptor (uPAR) expression positively correlates with reduced overall patient survival. Here, we tested the hypothesis that the expression and activity of plasminogen activation (PA) system components are functionally linked to PDAC tumor growth and disease progression. We generated C57Bl/6-derived KPC (i.e., KRasG12D, TRP53R172H) PDAC cell lines in which uPA and uPAR were knocked out using CRISPR-Cas9. We then analyzed orthotopic tumor growth and experimental metastasis in mice carrying null or functional mutations in uPA, uPAR, or plasminogen to evaluate the interplay of PA components derived from tumor cells and/or stromal cells in mediating PDAC progression. Although both KPC cell CRISPR variants retained procoagulant function, elimination of tumor cell uPA or uPAR yielded significantly smaller tumors when compared to Cas9 control tumor cells in wildtype mice. Similarly, the growth of WT KPC tumor cells in C57Bl/6 background uPA-KO or uPAR-KO mice also resulted in reduced tumor growth. To our surprise, the metastasis potential of WT KPC tumor cells in uPA-KO or uPAR-KO mice did not change when compared to wildtype mice. Regarding to the uPA/uPAR axis downstream effector plasminogen, the growth of WT KPC tumors in plasminogen-KO mice was also significantly reduced, but not to the same extent as when eliminating uPA or uPAR. In addition, eliminating plasminogen drastically reduced WT KPC tumor cells metastasis potential. In conclusion, our data suggest a mechanism whereby uPA functions through uPAR in both the tumor cell and stromal cell compartments to promote PDAC progression through plasminogen-dependent and -independent mechanisms. Citation Format: Yi Yang, Sara R. Abrahams, Aditi Kothari, Harshi Matada, Keely Davey, Alisa S. Wolberg, Matthew J. Flick. A uPA/uPAR axis in both the tumor cell and stromal compartment drives PDAC disease progression [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-127.

The Impact of SARS-CoV-2 Infection on Blood Coagulation and Fibrinolytic Pathways: A Review of Prothrombotic Changes Caused by COVID-19.

The cardinal pathology of coronavirus disease 2019 (COVID-19) is a primary infection of pulmonary tract cells by severe acute respiratory syndrome coronavirus 2, provoking a local inflammatory response, often accompanied by cytokine storm and acute respiratory distress syndrome, especially in patients with severe disease. Systemic propagation of the disease may associate with thrombotic events, including deep vein thrombosis, pulmonary embolism, and thrombotic microangiopathy, which are important causes of morbidity and mortality in patients with COVID-19. This narrative review describes current knowledge of the pathophysiological mechanisms of COVID-19-associated coagulopathy, with focus on prothrombotic changes in hemostatic mediators, including plasma levels of clotting factors, natural anticoagulants, components of fibrinolytic system, and platelets. It will also highlight the central role of endothelial cells in COVID-19-associated coagulopathy. This narrative review discusses also potential therapeutic strategies for managing thrombotic complications. Awareness by medical experts of contributors to the pathogenesis of thrombotic events in COVID-19 is imperative to develop therapeutics not limited to regular anticoagulants. Instituting cooperation among medical personnel and researchers may lessen this novel virus' impact now, and in the event of recurrence.

Advances on the components of fibrinolytic system in malignant tumors

The major function of fibrinolytic system is to dissolve the fibrins formed by blood coagulation and maintain the balance between blood coagulation and thrombolysis, which plays an important role in maintaining the liquid state of the blood and unclogging the blood vessels. It is a serious problem that malignant tumor does great harm to human life and health. In recent years, more and more studies signified that the fibrinolytic system in malignant tumors, especially adenocarcinoma, plays a major role in its progression, which indicates that the fibrinolytic system is of great significance in the development of malignant tumors. Besides, the fibrinolytic system has also gradually been known and used to diagnose and treat the adenocarcinoma. This article reviews how the fibrinolytic system works in the occurrence of malignant tumor and summarizes the diagnostic method and treatment of adenocarcinoma according to the latest clinical research progress, laying the foundation for further research.

Contributions of different modules of the plasminogen-binding Streptococcus pyogenes M-protein that mediate its functional dimerization.

Group A Streptococcus pyogenes (GAS) is a causative agent of pharyngeal and dermal infections in humans. A major virulence determinant of GAS is its dimeric signature fibrillar M-protein (M-Prt), which is evolutionarily designed in modules, ranging from a hypervariable extracellular N-terminal region to a progressively more highly conserved C-terminus that is covalently anchored to the cell wall. Of the >250 GAS isolates classified, only the subset of skin-trophic Pattern D strains expresses a specific serotype of M-Prt, PAM, that directly binds to host human plasminogen (hPg) via its extracellular NH2-terminal variable A-domain region. This interaction allows these GAS strains to accumulate components of the host fibrinolytic system on their surfaces to serve extracellular functions. While structure-function studies have been accomplished on M-Prts from Pattern A-C GAS isolates with different direct ligand binding properties compared to PAM, much less is known regarding the structure-function relationships of PAM-type M-Prts, particularly their dimerization determinants. To examine these questions, PAMs from seven GAS strains with sequence variations in the NH2-terminal ligand binding domains, as well as truncated versions of PAM, were designed and studied. The results from bioinformatic and biophysical analyses show that the different domains of PAM are disparately engaged in dimerization. From these data, we propose an experimentally-based model for PAM secondary and quaternary structures that is highly dependent on the conserved helical C-terminal C-D-domains. In addition, while the N-terminal regions of PAMs are variable in sequence, the binding properties of hPg and its activated product, plasmin, to the A-domain, remain intact.

Coexistence of endothelial dysfunction, fibrinolysis activation and diminished interleukin 6 level in morbid obesity

ABSTRAKTWstęp: Celem pracy była ocena wybranych parametrów dysfunkcji śródbłonka i hemostazy u chorych z otyłością. Badania dotyczące zaburzeń komórek śródbłonka w otyłości ogromnej są w literaturze spotykane zaskakująco rzadko.Materiały i metody: Badanie przeprowadzono u 74 chorych z otyłością ze wskaźnikiem masy ciała (BMI) >40 kg/m2 oraz u 30 zdrowych ochotników z prawidłowym BMI. W osoczu krwi chorych przeprowadzono testy stężenia: rozpuszczalnej formy trombomoduliny (sTM), antygenu czynnika von Willebranda (vWF:Ag), antygenu tkankowego aktywatora plazminogenu (t-PA:Ag) i antygenu inhibitora aktywatora plazminogenu typu 1 (PAI-1:Ag) oraz rozpuszczalnej frakcji selektyny E i P (sE-selektyny i sP-selektyny). Dokonano także pomiaru stężenia interleukiny 6 (Il-6).Wyniki: Wyniki badań wskazały znaczne zwiększenie stężenia sTM, t-PA:Ag, PAI-1:Ag i sE-selektyny oraz istotne zmniejszone stężenie vWF:Ag i sP-selektyny w otyłości ogromnej w porównaniu z grupą kontrolną. Wykazano także w otyłości ogromnej obniżenie stężenia Il-6.Wnioski: W otyłości ogromnej dochodzi do uszkodzenia śródbłonka, co zwiększa ryzyko ewentualnych powikłań zakrzepowo-zatorowych. Zwiększenie składowych układu fibrynolizy oraz hamowanie aktywacji płytek można traktować jako mechanizmy kompensacyjne zmniejszające ryzyko powikłań. Spadek stężenia Il-6 może być wyrazem ograniczania procesu zapalnego, ale równocześnie może to być przyczyna zwiększonej podatności na choroby infekcyjne.

Can fibrinolytic system components explain cognitive impairment in multiple sclerosis?

BackgroundThe fibrinolytic system is capable of modulating inflammatory and degenerative events within the central nervous system. Specifically, the plasminogen activator inhibitor-1 (PAI-1) has been associated with different pathological conditions in multiple sclerosis (MS) and its role in cognitive functioning is also known. Objectives and methodsTo study the association between plasma levels and the polymorphic variants of the PAI-1 gene and cognitive performance in MS. 176 patients were studied. Neuropsychological evaluation was performed with the Brief Repeatable Battery of Neuropsychological Tests (BRB-N). A Polymerase Chain Reaction (PCR) was used to determine PAI-1 4G/5G polymorphisms and quantification was performed using an Enzyme-Linked ImmunoSorbent Assay (ELISA). ResultsParticipants were categorized as not cognitively impaired (NCI; n=114) and cognitively impaired (CI; n=62). The NCI group had a higher percentage of heterozygous subjects but no statistical differences were found between the CI and NCI group. Neuropsychological functioning did not correlate with plasma levels of PAI-1 or its genetic polymorphism. It is noteworthy that PAI-1 plasma levels were related to neurological impairment. DiscussionCognitive impairment in MS is due to strategic focal lesions affecting regions and tracts involved in cognitive processes and to diffuse damage in the white and gray matter. This complex etiology could explain the absence of a relationship between the cognitive functioning and PAI-1 in patients with MS that has been found in vascular dementia or Alzheimer's disease. Plasma curves of PAI-1 and its measures in cerebrospinal fluid could help elucidate the role of PAI-1 in MS.

Components of tissue fibrinolytic system as markers for processes in tumors of female reproductive organs.

e17032 Background: Components of tissue fibrinolytic system are now considered as important agents providing progressive tumor growth. The purpose of the study was to analyze fibrinolytic system components in uterine and breast tumors. Methods: We studied tumor samples in breast cancer (BC, n=24), nodular type of fibrocystic breast disease (FBD, n-15) and uterine myoma (UM, n=14) and in synchronous BC and UM (n=12). Intact breast tissues (IBT, n=16) and intact myometrium (IM, n=14) were used as the control. Activity of plasmin (P), total content and activity of uPA-Ag and uPA-act, tPA-Ag and tPA-act were determined by ELISA; plasminogen (PG) concentration was measured by spectrophotometry (ACTICHROME PLG, USA). Results: uPA-Ag in solitary BC was 6.5 times higher and uPA-act – 4.5 times higher than in IBT. Concentration of tPA-Ag in 75% of BC patients exceeded the value in IBT by 2.1 times, and tPA-act in 87.5% – by 1.5 times. tPA-Ag and tPA-act in FBD tissues were similar to IBT values, while uPA-Ag and uPA-act were increased by 2.2 times each. uPA-Ag in BC in BC+UM exceeded the norm by 10.6 times, uPA-act – by 5.5 times; tPA-Ag in 75% of samples was 3.8 times higher than in IBT, and tPA-act – 2.7 times higher. uPA-Ag and uPA-act levels in UM in BC+UM were similar to IM values, while tPA-Ag and tPA-act exceeded the norm by 1.8 and 1.5 times, respectively. Both uPA and tPA levels and activity in solitary UM did not differ significantly from IM. Conclusions: The results show an active conversion of plasminogen into plasmin in both solitary and synchronous BC and in synchronous UM. Components of tissue fibrinolytic system can be considered as reliable markers for processes in solitary and synchronous tumors of female reproductive organs.

Ratio of some fibrinolytic system components and biological aggressiveness of melanoma.

e21069 Background: Melanomas of early stages in a horizontal growth phase can masquerade as a melanocytic nevus or other benign skin lesions. Activation of plasmin/plasminogen system is typical of both physiologic and pathologic processes. Cell remodeling and neoangiogenesis play critical role in melanoma invasion and metastasis. The purpose of the study was comparative analysis of plasmin/plasminogen system in tissues of nevi and melanomas of different sizes and extension. Methods: Activity of plasmin and plasminogen was studied and antigen and activity assays (ELISA) were performed for uPA, tPA and PAI-1 in tissues of nevi (n = 30) and melanomas pТ1-2N0M0 (n = 17) and pТ3-4N0-1M0 (n = 23). Intact tissue (n = 15) obtained in surgical treatment of patients without cancer was used for the control. Results: Plasminogen levels were decreased by 2 times in tissues of nevi and pТ1-2N0M0 melanoma, while plasmin was unchanged. pТ1-2N0M0 melanoma significantly differed from nevi by a marked activation of uPA without PAI-1 increase. Activation of plasminogen system in both рТ1-2N0M0 melanoma and in nevi was not accompanied by plasmin accumulation. The main difference between tissues of nevi and pТ1-2N0M0 melanoma was the uPA/PAI-1 ratio reduction by more than 40 times in nevi. pТ3-4N0-1M0 melanoma was characterized by plasmin level increase by more than 19 times and uPA activity and content increase by 2.5 times, compared to pТ1-2N0M0, without an increase in PAI-1 activity. The uPA/PAI-1 ratio almost doubled. Conclusions: Normal plasmin levels in nevi and melanomas in a horizontal growth phase are probably the result of its inhibitors activity. Increased activity of fibrinolytic system, plasmin accumulation and uPA/PAI-1 increase in a vertical growth phase determine proliferative, invasive and metastatic potential of tumors.

The disorders of hemostasis system and thrombotic complications in oncologic patients having liver operation.

The surgical interventions in patients with malignant tumors of liver cause a development of various forms of syndrome of disseminated intravascular coagulation (DIC) with significant increasing of concentration of markers of intravascular blood coagulation against the background of dramatic decreasing of activity of factors of prothrombin complex, level of natural anti-coagulants and components of fibrinolytic system. The thrombosis of veins of various localization developed in 12 patients with subacute form of DIC. The application of low-molecular heparin in combination with concentrate of anti-thrombin III and freshly frozen plasma decreases intensity of intra-vascular blood coagulation and results in reduction of factors of coagulation and is an efficient and adequate method of treatment of thrombosis and thromboembolism of pulmonary artery in oncologic patients. The significant increasing of level of D-dimer, von Willebrand factor against the background of dramatic decreasing of prothrombin activity, content of antithrombin III and level of plasminogen are hemostasiologic factors of development of severe liver insufficiency. The corresponding timely diagnostic and correction permits to ameliorate results of surgical treatment of patients with malignant tumors of liver.

Binding of human plasminogen and high-molecular-mass kininogen by cell surface-exposed proteins of Candida parapsilosis.

Pathogenic microbes can recruit to their cell surface human proteins that are components of important proteolytic cascades involved in coagulation, fibrinolysis and innate immune response. Once located at the bacterial or fungal surface, such deployed proteins might be utilized by pathogens to facilitate invasion and dissemination within the host organism by interfering with functionality of these systems or by exploiting specific activity of the bound enzymes. Aim of the study presented here was to characterize this phenomenon in Candida parapsilosis (Ashford) Langeron et Talice - an important causative agent of systemic fungal infections (candidiases and candidemias) in humans. We have investigated the interactions of fungal surface-exposed proteins with plasminogen (HPG) and high-molecular-mass kininogen (HK) - the crucial components of human fibrinolytic system and proinflammatory/procoagulant contact-activated kinin-forming system, respectively. After confirming ability of the fungal surface-exposed proteins to bind HPG and HK, four of them - two agglutinin-like sequence (Als) proteins CPAR2_404780 and CPAR2_404800, a heat shock protein Ssa2 and a moonlighting protein 6-phosphogluconate dehydrogenase 1 - were purified using ion-exchange chromatography, gel filtration and chromatofocusing. Then, their affinities to HPG and HK were characterized with surface plasmon resonance measurements. The determined dissociation constants for the investigated protein-protein complexes were within a 10-7 M order for the HPG binding and in a range of 10-8-10-9 M for the HK binding. Detailed characterization of adsorption of these two important plasma proteins on the fungal cell surface may help to increase our understanding of molecular mechanisms of C. parapsilosis-dependent candidiasis.

Effect of fibrin degradation products on fibrinolytic process.

Fibrin clot lysis by plasminogen/plasmin system results in fibrin degradation products formation with subsequent release into bloodstream. The fragments contain specific binding sites for fibrinolytic system components and can interact with them. In this study, we investigated the way in which fibrin fragments effect fibrinolytic process. We have shown that high molecular weight products of fibrin degradation and fibrin fragments of DDE-complex and DD, but not end product Е3, stimulate plasmin formation. Additionally, components of DDE-complex mixture of fragments Е1 and Е2 have potentiation ability. The intermediate fibrin fragments hmFDPs and DDE attenuate clot lysis by plasmin and hmFDPs protect plasmin from α2-antiplasmin inhibition but under further fragmentation to endpoint fibrin fragments loose this ability. The plasma inhibitors reduce fibrinolytic system activity generated by the degradation products. Thus, fibrin fragments formed during the clot lysis can bind and move out fibrinolytic system components from clot volume and in this way result in clot resistance to hydrolysis.

Thrombosis in inflammatory bowel diseases: what’s the link?

Inflammatory bowel disease affects more than 2 million people in Europe, with almost 20% of patients being diagnosed in pediatric age. Patients with inflammatory bowel disease are at increased risk of thromboembolic complications which may affect patients’ morbidity and mortality. The risk of the most common thromboembolic events, such as deep venous thrombosis and pulmonary embolism, are estimated to be three-fold increased compared to controls, but many other districts can be affected. Moreover, patients with ulcerative colitis and Crohn’s disease experience thromboembolic events at a younger age compared to general population. Many factors have been investigated as determinants of the pro-thrombotic tendency such as acquired risk factors or genetic and immune abnormalities, but a unique cause has not been found. Many efforts have been focused on the study of abnormalities in the coagulation cascade, its natural inhibitors and the fibrinolytic system components and both quantitative and qualitative alterations have been demonstrated. Recently the role of platelets and microvascular endothelium has been reviewed, as the possible link between the inflammatory and hemostatic process.

Molecular mechanisms and clinical significance of fibrinolysis

Fibrinolysis is the process of proteolytic digestion of fibrin aimed in vivo at dissolving clots or thrombi to restore the blood flow. In blood, the fibrinolytic system comprises a network of interrelated biochemical reactions that occur predominantly on the surface of fibrin fibers, the structural scaffold of hemostatic clots and obstructive thrombi. This review provides a brief description of the fibrinolytic system components and of the most important fibrinolytic reactions, including their modulation. The central enzyme in fibrinolysis is plasmin, a serine protease formed from its inactive precursor, plasminogen, upon the action of proteins and enzymes, whose formation and/or activation is triggered by various pathological stimuli. Plasmin cleaves a variety of substrates other than fibrin and therefore is involved in a number of biological processes other than hemostasis and thrombosis. There are several mechanisms moderating the activity of fibrinolytic enzymes that may become altered in various diseases. When the ratio of blood pro-and antifibrinolytic compounds is altered, hyper-or hypofibrinolysis might develop that causes and/or exacerbates hemorrhage or thrombosis, respectively. The paper contains an original pathogenic classification of fibrinolytic disorders and describes mechanisms of the primary and secondary hypo-and hyperfibrinolysis in various pathological conditions. Diagnosis of fibrinolytic defects builds on clinical symptoms along with defining the time of serum clots dissolving in vitro and serum levels of molecular markers. The principles of laboratory diagnostics of pathological fibrinolysis, based on the comprehension of the molecular mechanisms of normal and impaired fibrinolytic reactions, are reviewed. Treatment of pathological fibrinolysis implies the correction of either hyper-or hypofibrinolytic conditions and, therefore, is based on the administration of either antifibrinolytics (ε-eminocaproic and tranexamic acids) or thrombolytics (mainly, plasminogen activators) in combination with other therapies against bleeding and thrombosis.

Indexes of the coagulation and fibrinolytic system components, markers of inflammation in patients with type 2 diabetes mellitus and obesity

The author presents the data on a study of the markers of inflammation levels and state of the coagulation and fibrinolytic system components systems in patients with type 2 diabetes mellitus (DM) and visceral obesity in connection with cardiovascular diseases risk factors. With this purpose, 56 patients have been followed up. The control group included 20 patients corresponding on age and durations of type 2 DM but without abdominal obesity. It has been shown that procoagulant changes are marked at absolute majority of type 2 DM patients with visceral obesity (94.6%), in 64.3% patients these changes were connected with the defeat of a few links of the coagulation blood system. The most frequent changes of hemostasis is an increase of activity of plasminogen activator inhibitor 1 (87.5%), that represents insufficiency of fibrinolysis; increase of activity of coagulation factor VIII (53.6%) and testifies to activating of external cascade of hemopexis, and insufficiency of the anticoagulating system of protein C (23.2%). Chronic subacute system inflammation in type 2 DM patients with visceral obesity shows up the reliable increase of concentration of markers of inflammation – fibrinogen and Ñ-reactive protein, and also by the decline of adiponectin level. Expressed of proinflammatory and procoagulanting changes in patients with type 2 DM and visceral obesity associated with the anthropometric and biochemical markers of obesity.

Intracameral concentrations of the fibrinolytic system components in patients with age-related macular degeneration

To detect the intracameral concentrations and activities of plasminogen and other components of the fibrinolytic system, and to investigate whether those concentrations and activities are higher in patients with age-related macular degeneration (AMD) in comparison to healthy controls. Prospective case series of 93 patients scheduled for standard phacoemulsification. Mean plasminogen activity in patients with non-exsudative AMD (n = 24) revealed to be 0.06%N, in patients with exudative AMD (n = 7) 0.03%N and in healthy controls (n = 43) 0.02%N (p = 0.38, ANOVA). Plasminogen activator inhibitor I (PAI-1) was detected in neither group. Alpha2-antiplasmin activity was 1.61 U/ml in the non-exudative AMD group (n = 27), 0 U/ml in the exudative AMD group (n = 7) and 0.54 U/ml in the control group (n = 48) (p = 0.1, ANOVA). Concentrations of plasmin-a2-antiplasmin complex (PAP) were detected at levels of 17.91 ng/ml in the non-exudative AMD group (n = 11), of 16.6 ng/ml in the exudative AMD group (n = 5), and of 17.43 ng/ml in the control group (n = 14) (p = 0.92, ANOVA). Plasminogen is present with a very low activity in aqueous humor. There are no significant differences in aqueous humor concentrations or activities of plasminogen and other components of the fibrinolytic system between patients with non-exudative AMD, exudative AMD, and healthy controls. Further studies should investigate vitreous samples instead of aqueous humor samples. A careful and accurate workup of obtained intraocular fluids is needed to detect the low concentrations and activities of the parameters analyzed.

Substance P is an early mediator of peritoneal fibrinolytic pathway genes and promotes intra-abdominal adhesion formation

BackgroundThe substance P (SP) or neurokinin-1 receptor pathway has been implicated in intra-abdominal adhesion formation, in large part through its effects on peritoneal fibrinolysis. This study investigates the role of SP as an early mediator of the messenger RNA (mRNA) expression of key components of the peritoneal fibrinolytic system and other fundamental adhesiogenic pathways. Materials and methodsIntra-abdominal adhesions were surgically induced in 28 rats using the ischemic button model. mRNA levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor 1 (PAI-1), hypoxia-inducible factors (HIFs) 1α and 2α, and vascular endothelial growth factor A (VEGF-A) were measured in adhesive button tissue taken at time 0 and 1, 3, 6, 12, and 24h after surgery in rats receiving an intraoperative peritoneal bolus (25mg/kg) of a neurokinin-1 receptor antagonist (NK-1RA) or saline. Peritoneal fluid fibrinolytic activity was measured in peritoneal lavages taken at the same time points. ResultsSP levels increased (P≤0.05) within 1h postoperatively followed by an increase (P≤0.05) in tPA mRNA expression from 3 to 6h after surgery along with a striking increase (P≤0.05) in PAI-1 mRNA expression from 3 to 12h. NK-1RA administration further increased (P≤0.05) tPA mRNA expression and significantly blunted the increase in PAI-1 mRNA levels. The NK-1RA increased (P≤0.05) fitbrinolytic activity in peritoneal fluid at 3, 12, and 24h after surgery. HIF-1α and VEGF-A mRNA expressions increased from 3 to 12h (P≤0.05) and from 1 to 3h (P≤0.05) after surgery, respectively, whereas HIF-2α mRNA expression steadily decreased. NK-1RA delayed the rise in HIF-1α mRNA and ablated the changes in HIF-2α and VEGF-A mRNAs. ConclusionsSP is a pleiotropic early regulator of mRNA levels of key adhesiogenic mediators after surgery, suggesting that it may be a viable therapeutic target.