fibrin and Glioma

The diagnostic capabilities of magnetic resonance imaging (MRI) have undergone continuous and substantial evolution by virtue of hardware and software innovations and the development and implementation of exogenous contrast media. Thirty years since the first MRI contrast agent was approved for clinical use, a reliance on MR contrast media persists, largely to improve image quality with higher contrast resolution and to provide additional functional characterization of normal and abnormal tissues. Further development of MR contrast media is an important component in the quest for continued augmentation of diagnostic capabilities. In this review we detail the many important considerations when pursuing the design and use of MR contrast media. We offer a perspective on the importance of chemical stability, particularly kinetic stability, and how this influences one's thinking about the safety of metal-ligand-based contrast agents. We discuss the mechanisms involved in MR relaxation in the context of probe design strategies. A brief description of currently available contrast agents is accompanied by an in-depth discussion that highlights promising MRI contrast agents in the development of future clinical and research applications. Our intention is to give a diverse audience an improved understanding of the factors involved in developing new types of safe and highly efficient MR contrast agents and, at the same time, provide an appreciation of the insights into physiology and disease that newer types of responsive agents can provide.

Topics: Animals; Brain; Brain Neoplasms; Collagen; Contrast Media; Diffusion; Drug Design; Fibrin; Gadolinium; Glioma; Humans; Image Processing, Computer-Assisted; Kinetics; Ligands; Magnetic Resonance Imaging; Mice; Models, Chemical; Pentetic Acid; Thermodynamics; Water

The viscoelasticity of the crosslinked semiflexible polymer networks-such as the internal cytoskeleton and the extracellular matrix-that provide shape and mechanical resistance against deformation is assumed to dominate tissue mechanics. However, the mechanical responses of soft tissues and semiflexible polymer gels differ in many respects. Tissues stiffen in compression but not in extension

Topics: Adipose Tissue; Animals; Biomechanical Phenomena; Biopolymers; Blood Coagulation; Cell Count; Cell Line; Elasticity; Erythrocytes; Extracellular Matrix; Fibrin; Fibroblasts; Glioma; Humans; Male; Mice; Mice, Inbred C57BL; Models, Biological; Rats; Rats, Sprague-Dawley; Rheology

In human gliomas, tissue factor (TF) is overexpressed, associated with the grade of malignancy and influences tumour biology. Intra-tumoural fibrin/fibrinogen deposition and activation of the fibrinolytic system also play a role in tumour cell proliferation and angiogenesis. The first aim of the present study was to investigate TF expression and the presence of fibrin/fibrinogen and D-dimers in canine glioma biopsies, graded according to the World Health Organization (WHO) classification of tumours of the central nervous system. The second aim was to investigate the occurrence of intravascular thrombosis (IVT) in canine gliomas, as a potential histological marker of glioma type or grade of malignancy. An immunohistochemical study using antibodies against TF, fibrin/fibrinogen and D-dimers was performed with 24 glioma samples, including 15 oligodendrogliomas, 6 astrocytomas and 3 mixed gliomas. Immunohistochemical data were statistically analysed to determine whether there was any relationship between glioma type and grade of malignancy. All gliomas were moderate to strongly positive for TF and the staining score was significantly higher (P = 0.04) in high-grade (III or IV) than in low-grade (II) gliomas. Intra-tumoural fibrin/fibrinogen deposition was detected in all tumour biopsies assessed, and D-dimers were detected in 17/24 gliomas. IVT was a frequent finding, but was not linked to a specific glioma type or malignancy grade. TF expression, fibrin/fibrinogen deposition, extravascular fibrinolytic system activation and IVT occur in canine gliomas. Canine glioma might be a suitable model for studying coagulation and fibrinolysis as potential therapeutic targets for human gliomas.

Topics: Animals; Astrocytoma; Biomarkers; Dog Diseases; Dogs; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Gene Expression; Glioma; Immunohistochemistry; Oligodendroglioma; Spain; Thromboplastin; Thrombosis

Cell-based therapies have intriguing potential for the treatment of a variety of neurological disorders. One such example is genetically engineered cytotoxic T lymphocytes (CTLs) that are being investigated in brain tumor clinical trials. The development of methods for CTL delivery is critical to their use in the laboratory and clinical setting. In our study, we determined whether CTLs can migrate through fibrin matrices and if their migration, survival, and function could be modulated by adding chemokines to the matrix. Our results indicated that CTLs can freely migrate through fibrin matrices. As expected, the addition of the monocyte chemotactic protein-1 (MCP-1), also known as chemokine C-C motif ligand 2 (CCL2), to the surrounding media increased egress of the CTLs out of the fibrin clot. Interleukin (IL) -2 and/or IL-15 embedded in the matrix enhanced T cell survival and further promoted T cell migration. The interleukin-13 receptor alpha 2 specific (IL-13R alpha2) T cells that traveled out of the fibrin clot retained the capacity to kill U251 glioma cells. In summary, CTLs can survive and migrate robustly in fibrin matrices. These processes can be influenced by modification of matrix constituents. We conclude that fibrin matrices may be suitable T cell carriers and can be used to facilitate understanding of T cell interaction with the surrounding microenvironment.

Topics: Brain Neoplasms; Cell Movement; Cell Survival; Cells, Cultured; Chemokine CCL2; Fibrin; Glioma; Humans; Interleukin-15; Interleukin-2; T-Lymphocytes, Cytotoxic

To compare a fibrin-targeted, high relaxivity gadolinium tetramer, EP-2104R, in terms of magnitude of contrast enhancement (CE) and temporal time course, to a conventional extracellular gadolinium chelate, in a brain glioma model at 1.5-T magnetic resonance imaging.. Six rats were evaluated, with each animal receiving (for separate studies) 0.05 mmol/kg gadopentetate dimeglumine (Gd DTPA or Magnevist) and 0.0125 mmol/kg of EP-2104R, with the 2 magnetic resonance examinations separated in each animal by 24 hours. The compound (EP-2104R) was synthesized using published methodology, being comprised of an 11 amino acid peptide derivatized at both the C- and N-termini with Gd-DOTA-like (Dotarem-like) moieties. T1-weighted scans were acquired precontrast and for 5 consecutive 2-minute intervals postcontrast, and subsequently at 15 and 20 minutes postcontrast.. Maximum tumor contrast-to-noise and CE both occurred at 1 minute versus at 5 minutes following administration of Gd DTPA versus EP-2104R, respectively. Utilizing an equivalent dose on a Gd ion per body weight basis, signal-to-noise, contrast-to-noise, and CE were greater for EP-2104R at all time points postcontrast, yielding overall statistically significantly greater levels of all 3 parameters with the latter. With EP-2104R, improvements in CE ranged between 87% and 391%, increasing at each measured time postcontrast with the exception of a slight decrease from 15 to 20 minutes postadministration. Histopathology confirmed, using immunofluorescence technique, abnormally increased fibrin within the tumor.. Statistically significantly greater brain tumor enhancement was noted with greater lesion enhancement at all observed time points postcontrast for EP-2104R utilizing an equivalent concentration to Gd DTPA on a per gadolinium ion basis. These findings together with the prolonged time course of enhancement suggest possible fibrin-binding and altered distribution kinetics.

Topics: Animals; Area Under Curve; Brain Neoplasms; Contrast Media; Disease Models, Animal; Fibrin; Fluorescent Antibody Technique, Direct; Gadolinium DTPA; Glioma; Heterocyclic Compounds; Organometallic Compounds; Rats; Rats, Inbred F344

For tumor growth, proteolytic remodeling of the extracellular matrix (ECM) is a key factor. To determine proteolytic activity in human glioma cells, fibrinolytic activity, mRNA expression of fibrinolytic factors, and fibrinolytic inhibitors were studied in human glioma cell lines. The effect of platelet activating factor (PAF), a potent mediator of inflammatory and immune responses, on this fibrinolytic activity was also examined.. The fibrinolytic activities of conditioned medium and cell lysates from human glioma cell lines, A172, T98G, U87 and TM1 were studied by fibrin plate zymography. mRNA expression of tissue plasminogen activator (tPA), urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitors (PAI-1, PAI-2) was measured by Northern blot analysis. PAF was added to the medium, and its effects on cell proliferation, fibrinolytic activity, mRNA expression of plasminogens and inhibitors were studied.. mRNA expression of plasminogens and inhibitors differed between individual cell lines. Only the medium and cell lysates from A172 cells revealed fibrinolytic activity. A172 cells showed mRNA expression of tPA. PAF at low concentrations, such as 1 nM, stimulated A172 cell proliferation, and high concentrations of PAF inhibited proliferation. PAF stimulated tPA release into the conditioned medium. mRNA expression of tPA was stimulated by low concentrations of PAF and inhibited by high concentrations.. The variability of mRNA expression of plasminogen activators (PAs) between different glioma cell lines may indicate that plasminogens and their inhibitors do not directly correlate with brain tumor growth. PAF may be an important factor in the local control of fibrinolytic activity in glioma and its proliferation.

Topics: Blotting, Northern; Brain Neoplasms; Cell Division; Culture Media, Conditioned; Enzyme-Linked Immunosorbent Assay; Fibrin; Fibrinolysis; Gene Expression Regulation, Neoplastic; Glioma; Humans; Plasminogen Activator Inhibitor 1; Plasminogen Activator Inhibitor 2; Platelet Activating Factor; RNA, Messenger; Tissue Plasminogen Activator; Tumor Cells, Cultured; Urokinase-Type Plasminogen Activator

Glioma cells, a human astrocyte-derived glioma cell line, were found to spread on immobilized fibrin monomer but not on fibrinogen. As a synthetic RGD-containing peptide GRGDSP blocked the spreading of glioma cells on fibrin monomer concentration-dependently, the spreading was thought to be mediated by their cell surface receptors. In fact, both the beta1- and beta3-integrins were located at 3 hours of incubation in the cytoplasmic areas and at 24 hours in the peripheral areas as well, although their distribution profiles were not necessarily identical with each other by immunohistochemical studies. By cytometry analysis utilizing respective monoclonal antibodies against alpha5- and alpha v-integrins, we were able to show expression of alpha5 (alpha5beta1) but not alpha v on the surface of glioma cells at 24 hours of incubation on immobilized fibrin monomer. A 50-kDa transmembrane protein designated as integrin-associated protein (IAP) known to be closely associated with the beta3-integrin was also located in the cytoplasmic and apical areas of spreading glioma cells, but its specific antibody B6H12 failed to inhibit the spreading. Thus, the IAP-dependent involvement of beta3-integrin may not be predominantly involved in the glioma cell spreading on fibrin monomer. As an anti-alpha v beta3 antibody LM 609 inhibited the spreading of glioma cells partially at approximately 35%, the spreading seems to proceed in a two-step mode, i.e., via alpha vbeta3 with its ligand exposed in fibrin monomer, and then via alpha5beta1 with endogenous cellular fibronectin secreted from the glioma cells themselves. In fact, the cellular fibronectin was clearly visualized by confocal microscopic observation. Thus, upon contact with fibrin in clots formed at traumatized areas in the brain, for example, glioma cells may have a chance to adhere to and spread via alpha v beta3 with fibrin monomer and then via alpha5beta1 with endogenous cellular fibronectin in the extracellular matrices.

Topics: Cell Adhesion; Extracellular Matrix; Fibrin; Fibronectins; Glioma; Humans; Receptors, Fibronectin; Receptors, Vitronectin; Tumor Cells, Cultured

The cell-surface urokinase plasminogen activator receptor (uPAR) plays a key role in regulating plasminogen cleavage during extracellular proteolysis. Our recent results demonstrated that uPAR expression is critical for the invasiveness of human gliomas and down regulation of uPAR caused by antisense cDNA transfection inhibits the invasion of these stable antisense uPAR-transfectant clones. To study the role of uPARs in glioma cell invasion, a human neuroglioma cell line (H4) that normally produces low numbers of uPARs was transfected with the expression vector containing full-length human uPAR cDNA. Stable transfectants were analyzed for uPAR mRNA expression, receptor number, in vitro invasion and secretion of uPA and MMP-2. The uPAR-overproducing clones showed a 4-fold increase in uPAR mRNA transcription and approximately 40% increase in receptor numbers. uPAR-overproducing clones also invaded through matrigel to a significantly greater extent than did parent cell line and vector clones. However, the uPAR-overexpressing clones and parent cell lines showed similar uPA and MMP-2 activities. These results suggest that the over-production of uPAR on the surface of neuroglioma cells enhances the invasiveness.

Topics: Binding Sites; Blotting, Northern; DNA, Complementary; Fibrin; Gelatinases; Glioma; Humans; Matrix Metalloproteinase 2; Metalloendopeptidases; Neoplasm Invasiveness; Receptors, Cell Surface; Receptors, Urokinase Plasminogen Activator; RNA, Messenger; Transfection; Tumor Cells, Cultured; Urokinase-Type Plasminogen Activator

Because recent information suggests that the localized deposition of protease inhibitors is one mechanism by which cells regulate pericellular proteolysis during tissue invasion, the distribution of type 1 plasminogen activator inhibitor (PA1-1) associated with the invasive human glioma cell line U-251 was investigated. Direct and reverse fibrin zymography indicated the presence of urokinase-like plasminogen activator (u-PA) and PAI-1 in U-251 conditioned media and cell lysates. PA1-1 antigen was detected immunologically in cytoplasmic granules present within cellular processes of U-251 cells and these organelles could be isolated on Percoll density gradients in a high density band. In contrast, u-PA activity and another secreted protein, amyloid beta-protein precursor, were only present in the low density region of the gradients. Functional analysis of PAI-1 in the granules contained within the high density fractions revealed the presence of active PAI-1. Incubation of U-251 cells with the secretagogue, 8-bromoadenosine 3':5'-cyclic monophosphate, resulted in a 3-fold increase in the release of PAI-1 in the media conditioned by these cells. These data suggest that the human glioma cell line U-251 contains PAI-1 in a rapidly releasable form, which may provide another mechanism by which these tumors could regulate proteolytic activity in a localized manner.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Cell Fractionation; Cell Line; Centrifugation, Density Gradient; Fibrin; Fibrinolysis; Glioma; Humans; Immunohistochemistry; Neoplasm Invasiveness; Organelles; Plasminogen Activator Inhibitor 1; Povidone; Silicon Dioxide; Tumor Cells, Cultured; Urokinase-Type Plasminogen Activator

Topics: Animals; Antigens; Brain Neoplasms; Carcinoma, Ehrlich Tumor; Fibrin; Fibrinogen; Fluorescent Antibody Technique; Glioblastoma; Glioma; Humans; Immunodiffusion; Immunoelectrophoresis; Iodine Isotopes; Meningioma; Mice; Neoplasms, Experimental; Plasminogen; Rabbits; Radiometry; Radionuclide Imaging; Rats; Sarcoma, Yoshida