fibrin and Hypertrophy

The growth plate (physis) is responsible for enabling and regulating longitudinal growth of upper and lower limbs. This regulation occurs through interaction of the cells in the growth plate with systemic and locally produced factors. This complex interaction leads to precisely controlled changes in chondrocyte size, receptors, and matrix, which ultimately result in endochondral bone formation. With advances in cellular and molecular biology, our knowledge about these complex interactions has increased significantly over the past decade. Deficiency of any of the regulating factors or physeal injury during childhood can alter this well-orchestrated sequence of events and lead to abnormalities in growth. This review highlights the histology of the normal physis, including recent findings at the cellular and molecular levels, mechanics and mechanobiology of the growth plate, pathologies that can affect the physis, and treatment options, including interposition materials.

Topics: Animals; Bone Marrow Cells; Cell Differentiation; Cell Proliferation; Chondrocytes; Epiphyses; Extracellular Matrix; Extremities; Fibrin; Growth Plate; Humans; Hypertrophy; Osteogenesis; Polymethyl Methacrylate; Signal Transduction; Stress, Mechanical

Bone tissue engineering using stem cells to build bone directly on a scaffold matrix often fails due to lack of oxygen at the injury site. This may be avoided by following the endochondral ossification route; herein, a cartilage template is promoted first, which can survive hypoxic environments, followed by its hypertrophy and ossification. However, hypertrophy is so far only achieved using biological factors. This work introduces a Bioglass-Poly(lactic-co-glycolic acid@fibrin (Bg-PLGA@fibrin) construct where a fibrin hydrogel infiltrates and encapsulates a porous Bg-PLGA. The hypothesis is that mesenchymal stem cells (MSCs) loaded in the fibrin gel and induced into chondrogenesis degrade the gel and become hypertrophic upon reaching the stiffer, bioactive Bg-PLGA core, without external induction factors. Results show that Bg-PLGA@fibrin induces hypertrophy, as well as matrix mineralization and osteogenesis; it also promotes a change in morphology of the MSCs at the gel/scaffold interface, possibly a sign of osteoblast-like differentiation of hypertrophic chondrocytes. Thus, the Bg-PLGA@fibrin construct can sequentially support the different phases of endochondral ossification purely based on material cues. This may facilitate clinical translation by decreasing in-vitro cell culture time pre-implantation and the complexity associated with the use of external induction factors.

Topics: Chondrogenesis; Fibrin; Glycols; Humans; Hydrogels; Hypertrophy; Osteogenesis; Polylactic Acid-Polyglycolic Acid Copolymer; Tissue Engineering; Tissue Scaffolds

The leptin deficient ob/ob mouse is a widely used model for studies on initial aspects of metabolic disturbances leading to type 2 diabetes, including insulin resistance and obesity. Although it is generally accepted that ob/ob mice display a dramatic increase in β-cell mass to compensate for increased insulin demand, the spatial and quantitative dynamics of β-cell mass distribution in this model has not been assessed by modern optical 3D imaging techniques. We applied optical projection tomography and ultramicroscopy imaging to extract information about individual islet β-cell volumes throughout the volume of ob/ob pancreas between 4 and 52 weeks of age. Our data show that cystic lesions constitute a significant volume of the hyperplastic ob/ob islets. We propose that these lesions are formed by a mechanism involving extravasation of red blood cells/plasma due to increased islet vessel blood flow and vessel instability. Further, our data indicate that the primary lobular compartments of the ob/ob pancreas have different potentials for expanding their β-cell population. Unawareness of the characteristics of β-cell expansion in ob/ob mice presented in this report may significantly influence ex vivo and in vivo assessments of this model in studies of β-cell adaptation and function.

Topics: Animals; Fibrin; Hypertrophy; Imaging, Three-Dimensional; Islets of Langerhans; Mice, Obese; Pancreas; Tomography, Optical

Structural extracellular matrix molecules gain increasing attention as scaffolds for cartilage tissue engineering owing to their natural role as a growth factor repository. We recently observed that a collagen-type I/III (Col-I/III) matrix, human recombinant transforming growth factor-beta (TGF-β) protein, and fibrin hydrogel (FG) combined to a biphasic construct provided sufficient long-term TGF-β support to drive in vitro chondrogenesis of human mesenchymal stem cells (hMSC). Here we ask whether FG and Col-I/III can both retain TGF-β, describe the influence of cell seeding on TGF-β release, and compare the molecular path of hMSC chondrogenic differentiation under soluble versus local TGF-β supply. Release of growth factor from scaffolds augmented with increasing amounts of TGF-β was analyzed over 7 days and chondrogenesis was assessed over 42 days. Low TGF-β release rates from Col-I/III as opposed to higher release from FG indicated that both molecules retained TGF-β, with Col-I/III being the superior storage component. Cell seeding enhanced TGF-β retention in FG by about threefold and almost stopped release beyond 24 h. TGF-β remained bioactive and supported MSC chondrogenesis without impairing the amount of proteoglycan and collagen-type II deposition per cell and per construct compared to standard scaffold-free MSC pellets supplied with soluble TGF-β. Local TGF-β, however, mediated lower cell content, less collagen-type X relative to collagen-type II deposition and no matrix metalloproteinase-13 up-regulation. In conclusion, cells quickly halted release of local TGF-β from FG, turning FG and Col-I/III into attractive TGF-β repositories capable to drive full hMSC chondrogenesis, but via a modulated differentiation pathway. Since only part of the changes was reproduced by transient soluble TGF-β supply, release kinetics alone could not explain the molecular differences, suggesting that local TGF-β acts distinct from its soluble counterpart.

Topics: Biocompatible Materials; Cell Differentiation; Chondrogenesis; Collagen Type II; Fibrin; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate; Hypertrophy; Kinetics; Mesenchymal Stem Cells; Middle Aged; Proteoglycans; Solubility; Tissue Scaffolds; Transforming Growth Factor beta

The active type of coagulation factor X (factor Xa) activates various cell-types through protease-activated receptor 2 (PAR2). We previously reported that a factor Xa inhibitor could suppress Thy-1 nephritis. Considering that fibrin deposition is observed in diabetic nephropathy as well as in glomerulonephritis, this study examined the roles of the coagulation pathway and factor Xa in the development of diabetic nephropathy using type 2 diabetic model mice. Diabetic (db/db) and normoglycemic (m+/m+) mice were immunohistochemically evaluated for their expression/deposition of PAR2, transforming growth factor (TGF)-β, fibrin, extracellular matrix (ECM) proteins, and CD31 at week 20. Significantly greater numbers of PAR2-positive cells and larger amounts of fibronectin, and collagen IV depositions were observed in the glomeruli of db/db mice than those in m+/m+ mice. Next, expression of PAR2 versus deposition of collagen IV and fibronectin was compared between week 20 and week 30, and the number of PAR2-positive cells in the glomeruli decreased in contrast with the increased accumulation of ECM proteins. In an intervention study, fondaparinux, a factor Xa inhibitor, was subcutaneously administered for ten weeks from week 10 to 20. Fondaparinux treatment significantly suppressed urinary protein, glomerular hypertrophy, fibrin deposition, expression of connective tissue growth factor, and ECM proteins deposition together with CD31-positive capillaries. These results suggest that coagulation pathway and glomerular PAR2 expression are upregulated in the early phase of diabetes, together with the increase of profibrotic cytokines expression, ECM proteins deposition and CD-31-positive vessels. Factor Xa inhibition may ameliorate glomerular neoangiogenesis and ECM accumulation in diabetic nephropathy.

Topics: Animals; Anticoagulants; Blood Coagulation; Capillaries; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Disease Progression; Extracellular Matrix Proteins; Factor Xa; Factor Xa Inhibitors; Fibrin; Fondaparinux; Hypertrophy; Kidney; Kidney Glomerulus; Male; Mice; Mice, Obese; Platelet Endothelial Cell Adhesion Molecule-1; Polysaccharides; Proteinuria; Receptor, PAR-2; Transforming Growth Factor beta; Up-Regulation

Rice bodies are free corpuscles of synovial origin with a cartilage-like appearance that may reach hundreds in number in the intra-articular space. Rheumatologic or infectious pathologies that may produce synovial hypertrophy play a major role in the etiology. Already recognized by rheumatologists, this entity is rarely reported in orthopaedic literature. Numerous particles in the size and form of rice bodies were noted in the knee joint of an 11-year-old patient who underwent arthroscopic drainage and partial synovectomy. Histopathologic examination showed that some of the rice bodies consisted only of fibrin and some of them included a collagenous nucleus surrounded by a fibrin layer. No evidence of recurrence was observed by orthopaedic and rheumatologic evaluations within 2.5 years after the arthroscopic procedure.

Topics: Arthroscopy; Child; Collagen; Debridement; Fibrin; Foreign Bodies; Humans; Hypertrophy; Knee Joint; Male; Radiography; Range of Motion, Articular; Synovectomy; Synovial Membrane; Treatment Outcome

We observed the healing process under rigid external fixation after Salter-Harris type-1 or type-2 physeal separation at the proximal tibia in immature rabbits. Metaphyseal vessels grew across the gap with little delay; the site of separation then came to lie in the metaphysis and was bridged by endochondral ossification. Union was achieved within two days in all rabbits. Progression of endochondral ossification repaired the separated physis, thus showing 'primary healing of physeal separation'. This depends on accurate reduction and stable fixation to allow the survival of vessels across the gap.

Topics: Animals; Bone Nails; Epiphyses; Epiphyses, Slipped; External Fixators; Female; Fibrin; Follow-Up Studies; Growth Plate; Hemorrhage; Hypertrophy; Osteogenesis; Rabbits; Stainless Steel; Tibia; Wound Healing

Basic fibroblast growth factor (bFGF) can stimulate the proliferation and differentiation of keratinocytes, fibroblasts, and endothelial cells. These cells are involved during the healing of tympanic membrane (TM) perforations. Light and electron microscopy examinations were used to study the histology of TM healing after application of 400 ng of bFGF on the perforation. The progress of healing is accelerated, but the basic healing process is unchanged, i.e., epithelial proliferation first closes the perforation and is then followed by connective tissue growth. There is more connective tissue in the TM receiving bFGF, and extracellular fibers are better oriented. No significant increase of neoangiogenesis was detected in the treated TM. In the nonperforated area of treated TM, an extensive hyperplasia of the submucosal connective tissue is observed. These results demonstrate that bFGF can produce a TM scar containing more connective tissue, which may be of benefit in the prevention of atrophic healed TM.

Topics: Animals; Basement Membrane; Cell Division; Connective Tissue; Epithelium; Exudates and Transudates; Fibrin; Fibroblast Growth Factor 2; Fibroblasts; Hyperplasia; Hypertrophy; Keratins; Male; Microscopy, Electron; Neutrophils; Rats; Rats, Sprague-Dawley; Tympanic Membrane; Wound Healing

Malignant renal hypertension was induced in male Wistar rats. In the early phase of the disease, ie. the 1st week, a transient and generalized activation of arterial cellular functions was observed, while later, on day 21 widespread intimal proliferations developed in the arteries. This early activation included an increase in transmural permeability, DNA-, protein, collagen, elastin and ground substance synthesis, a rise in mural PGI2 content and an increase in number of Weibel-Palade bodies. An activation of platelets and monocytes could also be detected during the 1st week. In a group of rats the development of malignant hypertension was interrupted following the early activation of arteries and the incidence of intimal proliferations was compared with that of rats with maintained hypertension. No intimal proliferation was observed on day 21 in the rats with interrupted hypertension. It is concluded that the early activation of the artery does not furnish enough stimulus for triggering intimal proliferations and intimal plaques are not direct sequelae of the early arterial reaction. Furthermore the entrance of plasma materials during transmural permeability increase can not induce smooth muscle proliferation if the hypertension is interrupted.

Topics: Animals; Aorta; Arteries; Arterioles; Cell Membrane Permeability; Endothelium; Fibrin; Hypertension, Renovascular; Hypertrophy; Iron; Male; Microscopy, Electron; Muscle, Smooth, Vascular; Necrosis; Rats; Rats, Inbred Strains; Renin

Owing to special reactivity anchored in its structure the connective tissue responds to all kinds of injuries with tissue changes which in their completeness are designated as inflammation. An expressive carrier of mesodermal inflammation is the synovial membrane in which these tissue changes are manifested at first by the vessels and cells of the blood, and subsequently by all other constituents of the synovial membrane.

Topics: Collagen; Fibrin; Fibroblasts; Humans; Hypertrophy; Inflammation; Necrosis; Synovial Membrane; Synovitis; Time Factors

The studies reviewed here emphasize both the complexity and the heterogeneity of cell-mediated immunity. In addition to the round cell infiltrate of the classic descriptions, cell-mediated immunity includes reactions that feature many types of inflammatory cells, that exert profound effects on the blood microvasculature, and that initiate extravascular clotting and, possibly, angiogenesis. The common denominator of all of these reactions is a subset or subsets of sensitized T lymphocytes that, on exposure to specific antigen, recruit and collaborate in other ways with one or more populations of circulating bone marrow-derived cells. Although the reactions generally resemble chronic inflammation by virtue of the lymphocytes and monocytes present, cell-mediated immunity may also take the guise of acute or subacute inflammation when neutrophils or eosinophils predominate and an entirely different morphologic pattern when basophils predominate, as in CBH. Tissue mast cells undergo changes (activation, proliferation) that are generally observed at later stages of delayed hypersensitivity, but no convincing evidence has been presented that these cells play an essential role in the elicitation of cell-mediated immunity. The concept that an essential prerequisite for the elicitation of delayed hypersensitivity is the mast cell-dependent generation of microvascular gaps, favoring inflammatory cell diapedesis, is clearly incorrect. First, lymphocytes fail to traverse certain of the vessels that exhibit such gaps (i.e., those of the SCV) in delayed hypersensitivity reactions in humans. Second, there is no diminution in the cellular infiltration associated with cell-mediated immunity reactions in mast cell-deficient mice. Cell-mediated immunity does not consist of an inflammatory cell infiltrate alone. The local microvasculature is rendered hyperpermeable to varying extents, with resulting extravasation of plasma proteins, including fibrinogen. The majority of extravasated fibrinogen is clotted to cross-linked fibrin, presumably as the result of the actions of procoagulants associated with fixed connective tissue cells and perhaps also because of the activity of infiltrating cells, such as monocytes/macrophages. Clotted fibrin forms a water-trapping gel, which accounts for the induration seen in many delayed hypersensitivity reactions. The microvasculature may also be affected in other ways. Endothelial cells may undergo hypertrophy and cell division or, alternativel

Topics: Animals; Basophils; Blood Proteins; Blood Vessels; Capillaries; Capillary Permeability; Dermatitis, Contact; Endothelium; Fibrin; Guinea Pigs; Humans; Hypersensitivity, Delayed; Hypertrophy; Immunity, Cellular; Mice; Vasodilation

Immunoglobulins A, G, and M were localized in normal skin, hypertrophic scars, keloids, and mature scars by the direct immunofluorescent antibody method. All three immunoglobulins appeared increased in the lesions above levels observed in normal skin. Extractions of the immunoglobulins from the same type of tissues also suggested an increase above levels from normal skin. The data suggest attritional leakage of several plasma proteins from the microvasculature in the lesions. No one immunoglobulin appears significantly increased in the lesions compared with others.

Topics: Albumins; Cicatrix; Complement C3; Complement C4; Fibrin; Fluorescent Antibody Technique; Humans; Hypertrophy; Immunoglobulins; Keloid; Skin

Topics: Adolescent; Burns; Child; Cicatrix; Cytoplasm; Fibrin; Fibroblasts; Granulation Tissue; Humans; Hypertrophy; Infant

Topics: Animals; Aorta; Blood Vessel Prosthesis; Cats; Cell Movement; Endothelium; Fibrin; Humans; Hypertrophy; Microscopy, Electron, Scanning; Muscle, Smooth; Time Factors; Transplantation, Heterologous; Umbilical Arteries

Topics: Administration, Oral; Animals; Constriction; Dyspnea; Female; Fibrin; Growth; Heart Ventricles; Hemorrhage; Hypertrophy; Inclusion Bodies; Injections, Intraperitoneal; Iron; Liver; Lung; Lymphocytes; Mast Cells; Muscle, Smooth; Organ Size; Pulmonary Artery; Pulmonary Edema; Pulmonary Veins; Pyrrolizidine Alkaloids; Rats; Time Factors

Topics: Acetylcholine; Biopsy; Bradykinin; Burns; Capillary Permeability; Complement System Proteins; Edema; Epithelium; Fibrin; Fibrinolysis; Fluorescent Antibody Technique; Globulins; Histamine; Histological Techniques; Humans; Hypertrophy; Inflammation; Kallikreins; Leukocytes; Plasminogen; Serotonin; Skin; Time Factors; Urticaria

Topics: Animals; Arthritis; Carrageenan; Fibrin; Germ-Free Life; Hypertrophy; Lymphocytes; Phagocytosis; Rabbits; Swine; Swine Diseases; Synovial Fluid; Synovial Membrane