Prognostic Value of TRPM7 Expression and Factor XIIIa-Expressing Tumor-Associated Macrophages in Gastric Cancer

Purpose. TRPM7 is known to play a key role in tumor progression by regulating cellular proliferation, migration, and invasion in various cancer cell lines. However, there are no comprehensive clinical studies about the effect of TRPM7 expression on gastric cancer (GC) prognosis. In this study, it was aimed at investigating the effect of TRPM7 expression on prognosis in GC patients. Additionally, for the first time, it was investigated whether the density of Factor XIIIa-expressing tumor-associated macrophages (TAMs) in GC has an effect on the biological behaviour of the tumor. Methods. TRPM7 expression and Factor XIIIa-expressing TAM density were immunohistochemically evaluated in paraffin-embedded tumor tissues of 204 GC patients undergoing surgery at a single institution. Results. Tumor size was clearly higher in cases with high TRPM7 expression than those with low expression ( p < 0.001 , Mann-Whitney U ). TRPM7 overexpression was closely related to high depth of tumor invasion ( p < 0.001 , ANOVA), increased lymph node metastasis ( p < 0.001 , ANOVA), and high distant metastasis rate ( p < 0.001 , Mann-Whitney U ). These findings exposed that high TRPM7 expression is effective in the progression and aggressiveness of GC. In addition, while high CD8+ TIL density affects the prognosis positively, it was determined that high Factor XIIIa+ TAM density negatively affects the prognosis of patients with GC. Furthermore, multivariate analyses revealed TRPM7 overexpression was independently related with short overall (HR 9.64, 95% CI 5.74–16.19, p < 0.001 ) and disease-free survival (HR 5.67, 95% CI 3.61-8.92, p < 0.001 ) in GC patients. Conclusions. Our data suggest that high TRPM7 expression is closely related to progressive tumor behaviour in GC and independently negatively affects survival in patients. In addition, it was determined that a high density of Factor XIIIa+ TAMs negatively affects the prognosis of patients with GC.

Mass Spectrometric Identification of a Novel Factor XIIIa Cross-Linking Site in Fibrinogen

Transglutaminases are a class of enzymes that catalyze the formation of a protein:protein cross-link between a lysine and a glutamine residue. These cross-links play important roles in diverse biological processes. Analysis of cross-linking sites in target proteins is required to elucidate their molecular action on target protein function and the molecular specificity of different transglutaminase isozymes. Mass-spectrometry using settings designed for linear peptide analysis and software designed for the analysis of disulfide bridges and chemical cross-links have previously been employed to identify transglutaminase cross-linking sites in proteins. As no control peptide with which to assess and improve the mass spectrometric analysis of TG cross-linked proteins was available, we developed a method for the enzymatic synthesis of a well-defined transglutaminase cross-linked peptide pair that mimics a predicted tryptic digestion product of collagen I. We then used this model peptide to determine optimal score thresholds for correct peptide identification from y- and b-ion series of fragments produced by collision-induced dissociation. We employed these settings in an analysis of fibrinogen cross-linked by the transglutaminase Factor XIIIa. This approach resulted in identification of a novel cross-linked peptide in the gamma subunit. We discuss the difference in behavior of ions derived from different cross-linked peptide sequences and the consequent demand for a more tailored mass spectrometry approach for cross-linked peptide identification compared to that routinely used for linear peptide analysis.

Challenges in the Histopathologic Diagnosis of Histiocytic Neoplasms

Histiocytic neoplasms, including Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), and Rosai-Dorfman disease (RDD), present a diagnostic challenge due to nonspecific fibroinflammatory infiltrates and a diverse clinical presentation. The pathologist can play a key role in classification of these disorders through multidisciplinary collaboration and correlation of pathologic features with clinical and radiologic findings. The histopathologic differential diagnosis is broad, requiring knowledge of the possible diagnoses at each specific anatomic site, and a careful assessment to exclude other inflammatory and neoplastic disorders. An immunohistochemistry panel including CD163, CD1a, langerin, S100, Factor XIIIa, OCT2, and BRAF V600E can provide definitive diagnosis in LCH and RDD, whereas ECD requires classic clinical features as well as confirmation of an activating MAPK pathway mutation by genetic studies.

Report of Two Cases of ALK-Positive Histiocytosis in Young Children with Localized Lesions

Introduction/Objective ALK-positive histiocytosis is a recently described entity which occurs in both children and adults and can present with localized or disseminated disease. Limited case reports and series describe histiocytic infiltrates with irregular morphologic features and typical immunoreactivity for CD68, CD163, lysozyme, S100(variable), CD4, and cytoplasmic ALK. ALK rearrangements are often confirmed by FISH or molecular sequencing. The presence of such rearrangements may make ALK inhibitor therapy possible, although further investigation is necessary. We report two cases of ALK-positive histiocytosis diagnosed at our institution. Methods/Case Report Patient 1 is a 4-year-old girl with a prior history of high-risk neuroblastoma status-post resection, bone marrow transplant, radiation, and chemotherapy. An MRI performed due to neurologic symptoms revealed a left frontal-enhancing mass. With concern for metastatic neuroblastoma, a biopsy was performed, which showed brain parenchyma infiltrated by large atypical histiocytes with moderate eosinophilic cytoplasm and irregular folded nuclei. The histiocytes stained positive for CD68, lysozyme, Factor XIIIa, CD163, CD4, S100(variable), and cytoplasmic ALK. An ALK rearrangement was confirmed by FISH studies. The patient is reportedly doing well on therapy. Patient 2 is a previously healthy 2-year-old boy with a midline palate lesion. An incisional biopsy revealed a submucosal infiltrate of small lymphocytes and enlarged atypical histiocytes with abundant eosinophilic cytoplasm and vesicular folded nuclei. Histiocytes stained positive for CD68, CD163, Factor XIIIa, lysozyme, S100(variable), CD4, and cytoplasmic ALK. Given presence of an ALK rearrangement detected by FISH, the patient was started on single agent crizotinib therapy and has responded with near complete resolution. Results (if a Case Study enter NA) NA Conclusion ALK-positive histiocytosis is a clinicopathologically distinct entity with predilection for young children and presence of ALK rearrangements which may be amenable to ALK inhibitors, such as crizonitib. We report two additional cases to contribute to the expanding spectrum of this rare and relatively new entity.

Lignosulfonic Acid Sodium Is a Noncompetitive Inhibitor of Human Factor XIa

The anticoagulant activity of lignosulfonic acid sodium (LSAS), a non-saccharide heparin mimetic, was investigated in this study. LSAS is a relatively safe industrial byproduct with similar polyanionic characteristics to that of heparin. Human plasma clotting assays, fibrin polymerization testing, and enzyme inhibition assays were exploited to investigate the anticoagulant activity of LSAS. In normal human plasma, LSAS selectively doubled the activated partial thromboplastin time (APTT) at ~308 µg/mL. Equally, LSAS doubled APTT at ~275 µg/mL in antithrombin-deficient plasma. Yet, LSAS doubled APTT at a higher concentration of 429 µg/mL using factor XI-deficient plasma. LSAS did not affect FXIIIa-mediated fibrin polymerization at 1000 µg/mL. Enzyme assays revealed that LSAS inhibits factor XIa (FXIa) with an IC50 value of ~8 μg/mL. LSAS did not inhibit thrombin, factor IXa, factor Xa, factor XIIIa, chymotrypsin, or trypsin at the highest concentrations tested and demonstrated significant selectivity against factor XIIa and plasmin. In Michaelis–Menten kinetics, LSAS decreased the VMAX of FXIa hydrolysis of a tripeptide chromogenic substrate without significantly changing its KM indicating an allosteric inhibition mechanism. The inhibitor also disrupted the generation of FXIa–antithrombin complex, inhibited factor XIIa-mediated and thrombin-mediated activation of the zymogen factor XI to FXIa, and competed with heparin for binding to FXIa. Its action appears to be reversed by protamine sulfate. Structure–activity relationship studies demonstrated the advantageous selectivity and allosteric behavior of LSAS over the acetylated and desulfonated derivatives of LSAS. LSAS is a sulfonated heparin mimetic that demonstrates significant anticoagulant activity in human plasma. Overall, it appears that LSAS is a potent, selective, and allosteric inhibitor of FXIa with significant anticoagulant activity in human plasma. Altogether, this study introduces LSAS as a promising lead for further development as an anticoagulant.

Ethacrynic Acid Is an Inhibitor of Human Factor XIIIa

Ethacrynic acid (EA) is a loop diuretic that is approved orally and parenterally to manage edema-associated diseases. Nevertheless, it was earlier reported that it is also associated with bleeding upon its parenteral administration. In this report, we investigated the effects of EA on human factor XIIIa (FXIIIa) of the coagulation process using a variety of techniques. FXIIIa is a transglutaminase that works at the end of the coagulation process to form an insoluble, rigid, and cross-linked fibrin rich blood clot. In fact, inhibition of FXIIIa-mediated biological processes has been reported to result in a bleeding diathesis. Inhibition of FXIIIa by EA was investigated given the nucleophilic nature of the thiol-containing active site of the enzyme and the Michael acceptor-based electrophilicity of EA. In a bisubstrate-based fluorescence trans-glutamination assay, EA inhibited FXIIIa with a moderate potency (IC50 ~ 105 µM) and efficacy (∆Y ~ 66%). In SDS-PAGE experiment, EA appears to significantly inhibit the FXIIIa-mediated polymerization of fibrin(ogen) as well as the formation of fibrin(ogen) – α2-antiplasmin complex which indicates that EA affects the physiological functions of FXIIIa. Interestingly, EA did not affect the clotting times of human plasma in the activated partial thromboplastin time (APTT) or prothrombin time (PT) assays at the highest concentration tested of 2.5 mM suggesting the lack of effects on the coagulation serine proteases and potentially the functional selectivity of EA with respect to the clotting process. Molecular modeling studies demonstrated that the Michael acceptor of EA forms a covalent bond with catalytic residue of Cys314 in the active site of FXIIIa. Overall, our studies indicate that EA inhibits the physiological function of human FXIIIa in vitro which may potentially contribute to the bleeding complications that were reported with the association of the parenteral administration of EA.

A Data Analysis of D-Dimer & Interleukin-6 (IL-6) Test for Covid Patient

Various biomarkers, especially inflammatory markers like C-reactive protein (CRP), ferritin, fibrinogen, D-dimer and Interleukin 6 (IL-6) are associated with Covid-19 progression. Thrombosis prophylaxis with low molecular weight heparin has shown beneficial results in preventing coagulopathy a reducing risk of mortality due to thrombotic events. The COVID-19 patients highlighting the role of D-dimer, and Interleukin-6 (IL-6). During plasma coagulation soluble fibrin is generated by the influence of thrombin on fibrinogen. The soluble fibrin is crosslinked to the vessel walls by factor XIIIa. When splitting this cross linked fibrin, characteristic products called D-dimers are released. Increased D-dimer concentrations are found in thrombotic diseases and microthrombotic events (e.g. in case of disseminated intravascular coagulation, DIC). D-dimer determination is mainly used to exclude deep vein thrombosis of the leg and pulmonary embolism. D-Dimer levels rise during pregnancy and high levels are associated with complications. D-dimer is a fibrin degradation product that is often used to measure and assess clot formation. Amid the COVID-19 pandemic, elevated D-dimer levels have been associated with disease severity and mortality trends. Interleukin-6 (IL-6) is a pro-inflammatory cytokine secreted by T cells and macrophages to stimulate immune response to trauma, especially burns or other tissue damage leading to inflammation. IL-6 is also secreted by macrophages in response to specific microbial molecules, referred to as Pathogen Associated Molecular Patterns (PAMPs), which trigger the innate immune response and initiate inflammatory cytokine production. IL-6 is one of the most important mediators of fever and of the acute phase response. IL-6 is also called a “myokine”, a cytokine produced from muscle that increases in response to muscle contraction. Additionally, osteoblasts secrete IL-6 to stimulate osteoclast formation. The detection and control of pro-inflammatory response is crucial in the early stages of viral infection. COVID-19 is an emerging viral disease of global concern and optimal treatment has yet to be determined. Unknown response of treatment of COVID-19 is important during patient monitoring. IL-6 is one of the key cytokines after activated macrophages. Here we will present a laboratory data analysis of COVID-19 patients in different age group highlighting the role of positivity D-dimer and interleukin-6 (IL-6).

Factor XIII cross-links fibrin(ogen) independent of fibrin polymerization in experimental acute liver injury

Intravascular fibrin clot formation follows a well-ordered series of reactions catalyzed by thrombin cleavage of fibrinogen leading to fibrin polymerization and cross-linking by factor XIIIa (FXIIIa). Extravascular fibrin(ogen) deposits are observed in injured tissues; however, the mechanisms regulating fibrin(ogen) polymerization and cross-linking in this setting are unclear. The objective of this study was to determine the mechanisms of fibrin polymerization and cross-linking in acute liver injury induced by acetaminophen (APAP) overdose. Hepatic fibrin(ogen) deposition and cross-linking were measured following APAP overdose in wild-type mice, mice lacking the catalytic subunit of FXIII (FXIII-/-), and in FibAEK mice, which express mutant fibrinogen insensitive to thrombin-mediated fibrin polymer formation. Hepatic fibrin(ogen) deposition was similar in APAP-challenged wild-type and FXIII-/- mice yet cross-linking of hepatic fibrin(ogen) was dramatically reduced (&gt;90%) by FXIII deficiency. Surprisingly, hepatic fibrin(ogen) deposition and cross-linking were only modestly reduced in APAP-challenged FibAEK mice, suggesting that in the APAP-injured liver fibrin polymerization is not strictly required for the extravascular deposition of cross-linked fibrin(ogen). We hypothesized that the oxidative environment in the injured liver, containing high levels of reactive mediators (e.g., peroxynitrite), modifies fibrin(ogen) such that fibrin polymerization is impaired without impacting FXIII-mediated cross-linking. Notably, fibrin(ogen) modified with 3-nitrotyrosine adducts was identified in the APAP-injured liver. In biochemical assays, peroxynitrite inhibited thrombin-mediated fibrin polymerization in a concentration-dependent manner without affecting fibrin(ogen) cross-linking over time. These studies depict a unique pathology wherein thrombin-catalyzed fibrin polymerization is circumvented to allow tissue deposition and FXIII-dependent fibrin(ogen) cross-linking.

Nonredundant Roles of Platelet Glycoprotein VI and Integrin αIIbβ3 in Fibrin-Mediated Microthrombus Formation

Objective: Fibrin is considered to strengthen thrombus formation via integrin αIIbβ3, but recent findings indicate that fibrin can also act as ligand for platelet glycoprotein VI. Approach and Results: To investigate the thrombus-forming potential of fibrin and the roles of platelet receptors herein, we generated a range of immobilized fibrin surfaces, some of which were cross-linked with factor XIIIa and contained VWF-BP (von Willebrand factor-binding peptide). Multicolor microfluidics assays with whole-blood flowed at high shear rate (1000 s −1 ) indicated that the fibrin surfaces, regardless of the presence of factor XIIIa or VWF-BP, supported platelet adhesion and activation (P-selectin expression), but only microthrombi were formed consisting of bilayers of platelets. Fibrinogen surfaces produced similar microthrombi. Markedly, tiggering of coagulation with tissue factor or blocking of thrombin no more than moderately affected the fibrin-induced microthrombus formation. Absence of αIIbβ3 in Glanzmann thrombasthenia annulled platelet adhesion. Blocking of glycoprotein VI with Fab 9O12 substantially, but incompletely reduced platelet secretion, Ca 2+ signaling and aggregation, while inhibition of Syk further reduced these responses. In platelet suspension, glycoprotein VI blockage or Syk inhibition prevented fibrin-induced platelet aggregation. Microthrombi on fibrin surfaces triggered only minimal thrombin generation, in spite of thrombin binding to the fibrin fibers. Conclusions: Together, these results indicate that fibrin fibers, regardless of their way of formation, act as a consolidating surface in microthrombus formation via nonredundant roles of platelet glycoprotein VI and integrin αIIbβ3 through signaling via Syk and low-level Ca 2+ rises.

RARE-40. CASE REPORT: LONG-TERM SURVIVOR OF A RARE, PEDIATRIC PRIMARY HISTIOCYTIC SARCOMA (HS) OF THE CENTRAL NERVOUS SYSTEM (CNS) FOLLOWING COMPLETE RESECTION, CHEMOTHERAPY AND ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION (ALLO-HCT)

We report an unusual case of a patient with primary CNS-HS a very rare neoplasm of histiocytic lineage with usually poor prognosis. An 8 year old boy presented with a one month history of headaches, nausea and vomiting. Physical examination revealed nystagmus and dysmetria. Brain MRI revealed a localized 2.4 cm posterior fossa (cerebellar) mass with restricted diffusion. The patient underwent a gross total resection of the mass. Initial post-operative lumbar puncture was positive for rare malignant cells. Pathology showed a focally necrotic neoplasm, composed of nests and cords of large relatively uniform cells with abundant eosinophilic cytoplasm, moderately pleomorphic nuclei and numerous mitotic figures, consistent with CNS-HS with juvenile xanthogranuloma phenotype, as supported by positive IHC expression of CD163, CD68, CD14, fascin, and Factor XIIIa, while negative for CD1a, Lymphoid and Myeloid markers, and BRAFv600e mutation. He was treated with two cycles of clofarabine and cytarabine and triple intrathecal (IT) chemotherapy. He developed generalized seizures and MRI showed demyelination consistent with IT methotrexate toxicity; MTX was then discontinued. He was then given two additional cycles of cladribine and weekly intrathecal therapy prior to consolidation with an Allo-HCT using a 10/10 HLA allelic-matched unrelated donor. His conditioning regimen included total body irradiation and cyclophosphamide. He did well post-transplant with peripheral blood chimerism at 1 year showing &gt; 95% donor cells. He remains disease-free with an excellent quality of life since August 2016. We report one of the few known survivors of this unusual and highly malignant entity.