transforming-growth-factor-beta and Eye-Diseases

Losartan is an angiotensin II receptor blocker (ARB) that impedes transforming growth factor (TGF) beta signaling by inhibiting activation of signal transduction molecule extracellular signal-regulated kinase (ERK). Studies supported the efficacy of topical losartan in decreasing scarring fibrosis after rabbit Descemetorhexis, alkali burn, and photorefractive keratectomy injuries, and in case reports of humans with scarring fibrosis after surgical complications. Clinical studies are needed to explore the efficacy and safety of topical losartan in the prevention and treatment of corneal scarring fibrosis, and other eye diseases and disorders where TGF beta has a role in pathophysiology. These include scarring fibrosis associated with corneal trauma, chemical burns, infections, surgical complications, and persistent epithelial defects, as well as conjunctival fibrotic diseases, such as ocular cicatricial pemphigoid and Stevens-Johnson syndrome. Research is also needed to explore the efficacy and safety of topical losartan for hypothesized treatment of transforming growth factor beta-induced (

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Cicatrix; Corneal Dystrophies, Hereditary; Corneal Injuries; Eye Diseases; Fibrosis; Humans; Losartan; Rabbits; Transforming Growth Factor beta

The TGF-β signaling pathway plays a crucial role in several key aspects of development and tissue homeostasis. TGF-β ligands and their mediators have been shown to be important regulators of ocular physiology and their dysregulation has been described in several eye pathologies. TGF-β signaling participates in regulating several key developmental processes in the eye, including angiogenesis and neurogenesis. Inadequate TGF-β signaling has been associated with defective angiogenesis, vascular barrier function, unfavorable inflammatory responses, and tissue fibrosis. In addition, experimental models of corneal neovascularization, diabetic retinopathy, proliferative vitreoretinopathy, glaucoma, or corneal injury suggest that aberrant TGF-β signaling may contribute to the pathological features of these conditions, showing the potential of modulating TGF-β signaling to treat eye diseases. This review highlights the key roles of TGF-β family members in ocular physiology and in eye diseases, and reviews approaches targeting the TGF-β signaling as potential treatment options.

Topics: Diabetic Retinopathy; Eye; Eye Diseases; Homeostasis; Humans; Neovascularization, Pathologic; Signal Transduction; Transforming Growth Factor beta

Cell transdifferentiation is the conversion of a cell type to another without requiring passage through a pluripotent cell state, and encompasses epithelial- and endothelial-mesenchymal transition (EMT and EndMT). EMT and EndMT are well defined processes characterized by a loss of epithelial/endothelial phenotype and gain in mesenchymal spindle shaped morphology, which results in increased cell migration and decreased apoptosis and cellular senescence. Such cells often develop invasive properties. Physiologically, these processes may occur during embryonic development and can resurface, for example, to promote wound healing in later life. However, they can also be a pathological process. In the eye, EMT, EndMT and cell transdifferentiation have all been implicated in development, homeostasis, and multiple diseases affecting different parts of the eye. Connexins, constituents of connexin hemichannels and intercellular gap junctions, have been implicated in many of these processes. In this review, we firstly provide an overview of the molecular mechanisms induced by transdifferentiation (including EMT and EndMT) and its involvement in eye diseases. We then review the literature for the role of connexins in transdifferentiation in the eye and eye diseases. The evidence presented in this review supports the need for more studies into the therapeutic potential for connexin modulators in prevention and treatment of transdifferentiation related eye diseases, but does indicate that connexin channel modulation may be an upstream and unifying approach for regulating these otherwise complex processes.

Topics: Animals; Cell Transdifferentiation; Connexins; Epithelial-Mesenchymal Transition; Eye Diseases; Humans; Signal Transduction; Transforming Growth Factor beta

Ocular fibrosis leads to severe visual impairment and blindness worldwide, being a major area of unmet need in ophthalmology and medicine. To date, the only available treatments are antimetabolite drugs that have significant potentially blinding side effects, such as tissue damage and infection. There is thus an urgent need to identify novel targets to prevent/treat scarring and postsurgical fibrosis in the eye. In this review, the latest progress in biological mechanisms underlying ocular fibrosis are discussed. We also summarize the current knowledge on preclinical studies based on viral and non-viral gene therapy, as well as chemical inhibitors, for targeting TGFβ or downstream effectors in fibrotic disorders of the eye. Moreover, the role of angiogenetic and biomechanical factors in ocular fibrosis is discussed, focusing on related preclinical treatment approaches. Moreover, we describe available evidence on clinical studies investigating the use of therapies targeting TGFβ-dependent pathways, angiogenetic factors, and biomechanical factors, alone or in combination with other strategies, in ocular tissue fibrosis. Finally, the recent progress in cell-based therapies for treating fibrotic eye disorders is discussed. The increasing knowledge of these disorders in the eye and the promising results from testing of novel targeted therapies could offer viable perspectives for translation into clinical use.

Topics: Eye Diseases; Fibrosis; Humans; Signal Transduction; Transforming Growth Factor beta

The term amyloidosis describes a group of rare diseases caused by protein conformation abnormalities resulting in extracellular deposition and accumulation of insoluble fibrillar aggregates. So far, 36 amyloid precursor proteins have been identified, and each one is responsible for a specific disease entity. Transthyretin amyloidosis (ATTRv) is one of the most common forms of systemic and ocular amyloidosis, due to the deposition of transthyretin (TTR), which is a transport protein mainly synthesized in the liver but also in the retinal pigment epithelial cells. ATTRv amyloidosis may be misdiagnosed with several other conditions, resulting in a significant diagnostic delay. Gelsolin and keratoepithelin are other proteins that, when mutated, are responsible for a systemic amyloid disease with significant ocular manifestations that not infrequently appear before systemic involvement. The main signs of ocular amyloid deposition are in the cornea, irido-corneal angle and vitreous, causing complications related to vasculopathy and neuropathy at the local level. This review aims at describing the main biochemical, histopathological and clinical features of systemic amyloidosis associated with eye involvement, with particular emphasis on the inherited forms. We discuss currently available treatments, focusing on ocular involvement and specific ophthalmologic management and highlighting the importance of a prompt treatment for the potential sight-threatening complications derived from amyloid deposition in ocular tissues.

Topics: Amyloid Neuropathies, Familial; Amyloidosis, Familial; Extracellular Matrix Proteins; Eye Diseases; Gelsolin; Genetic Predisposition to Disease; Humans; Prealbumin; Retinal Pigment Epithelium; Transforming Growth Factor beta

Wound healing is one of the most complex biological processes to occur in life. Repair of tissue following injury involves dynamic interactions between multiple cell types, growth factors, inflammatory mediators and components of the extracellular matrix (ECM). Aberrant and uncontrolled wound healing leads to a non-functional mass of fibrotic tissue. In the eye, fibrotic disease disrupts the normally transparent ocular tissues resulting in irreversible loss of vision. A common feature in fibrotic eye disease is the transdifferentiation of cells into myofibroblasts that can occur through a process known as epithelial-mesenchymal transition (EMT). Myofibroblasts rapidly produce excessive amounts of ECM and exert tractional forces across the ECM, resulting in the distortion of tissue architecture. Transforming growth factor-beta (TGFβ) plays a major role in myofibroblast transdifferentiation and has been implicated in numerous fibrotic eye diseases including corneal opacification, pterygium, anterior subcapsular cataract, posterior capsular opacification, proliferative vitreoretinopathy, fibrovascular membrane formation associated with proliferative diabetic retinopathy, submacular fibrosis, glaucoma and orbital fibrosis. This review serves to introduce the pathological functions of the myofibroblast in fibrotic eye disease. We also highlight recent developments in elucidating the multiple signaling pathways involved in fibrogenesis that may be exploited in the development of novel anti-fibrotic therapies to reduce ocular morbidity due to scarring.

Topics: Cell Transdifferentiation; Epithelial-Mesenchymal Transition; Eye Diseases; Fibrosis; Humans; Myofibroblasts; Signal Transduction; Transforming Growth Factor beta; Wound Healing

The eye is divided anatomically in three layers: an outer or fibrous layer (cornea/sclera), middle or vascular layer (uvea - iris, ciliary body, and choroid) and an inner or sensorineural layer (retina). They compose the several anatomic and functional layers that enable the immune protection of the eye. The first layer involves an intact anatomic border with the blood-ocular barrier and immunosuppressive neuropeptides in the native aqueous humor. The second layer trusts on the capability of the eye to reestablish an immunosuppressive micro-environment by activating latent TGF-β and reestablishing the anterior chamber-associated immune deviation. The third layer involves a mechanism that is not yet completely recognized, but that has the ability to overcome a predominantly Th1 intraocular immune response and to reestablish anterior chamber-associated immune deviation. Understanding the comprehensive mechanisms of these pathways, will lead to the development of new treatments strategies in order to prevent damage to the eye from persistent or exacerbated inflammation, directed at first to pathogens, but that may develop an autoimmune reaction.

Topics: Animals; Autoimmune Diseases; Eye Diseases; Humans; Transforming Growth Factor beta

The anterior segment of the eye ball, i. e., cornea and conjunctiva, serves as the barrier to the external stimuli. Cornea is transparent and is a "window"of the light sense, while conjunctiva covers the sclera, the main part of the eyeshell. Fibrosis/scarring in cornea potentially impairs vision by the reduction of its transparency and the alteration of the regular curvature. Fibrotic reaction in conjunctiva is also of a clinical importance because inflammatory fibrosis in this tissue affects the physiology of the cornea and also of a problem post-eye surgery. In this review we discuss on the topic that is quite critical in vision. Although various growth factors are considered to be involved in, focus was put on the roles of transforming growth factorβ (TGFβ).

Topics: Animals; Anterior Eye Segment; Cicatrix; Eye Diseases; Fibrosis; Humans; Inflammation Mediators; Signal Transduction; Transforming Growth Factor beta; Vision, Ocular

Transforming growth factor b (TGF beta) is believed to be the most important ligand in the pathogenesis of fibrotic diseases in the eye. Such ocular fibrotic diseases include scarring in the cornea and conjunctiva, fibrosis in the corneal endothelium, post-cataract surgery fibrosis of the lens capsule, excess scarring the tissue around the extraocular muscles in the strabismus surgery and proliferative vitreoretinopathy. In the proliferative stage of diabetic retinopathy, fibrogenic reaction causes tractional retinal detachment in association with contraction of the tissue. A myofibroblast, the major cellular component in the fibrotic lesions, is derived from both mesenchymal cells (in cornea and conjunctiva) and epithelial cell types (lens or retinal pigment epithelium or corneal endothelium) through epithelial-mesenchymal transition (EMT). The myofibroblasts cause excess accumulation of fibrogenic extracellular matrix with resultant tissue contraction and impaired functions. Although various cytokine signaling pathways are involved in the fibrogenic reaction in tissues, TGF beta/Smad signal is the critical one. Blocking Smad signal by chemical or natural inhibitors or anti-Smad gene introduction effectively suppress fibrogenic reaction; inhibition of both fibroblast-myofibroblast conversion or EMT. Such strategies can be clinically tested.

Topics: Epithelial Cells; Eye Diseases; Fibrosis; Humans; Mesoderm; Signal Transduction; Transforming Growth Factor beta

Fibrotic diseases, e.g., cutaneous and corneal scarring, keloids, and liver and lung fibrosis, etc., are characterized by appearance of myofibroblasts, the key player of the fibrogenic reaction, and excess accumulation of extracellular matrix with resultant tissue contraction and impaired functions. Inflammatory/fibrogenic growth factors/cytokines produced by injured tissues play a pivotal role in fibrotic tissue formation. Ocular tissues are also susceptible to fibrotic diseases. In this article, the pathogenesis of such fibrotic disorders in the eye, i.e., scarring in the cornea and conjunctiva, post-cataract surgery fibrosis of the lens capsule and proliferative vitreoretinopathy are reviewed. Focus is put on the roles of myofibroblast and signals activated by the fibrogenic cytokine, transforming growth factor beta. Modulation of signal transduction molecules, e.g., Smad and mitogen-activated protein kinases, by gene transfer and other technology is beneficial and can be an important treatment regiment to overcome (prevent or treat) these diseases.

Topics: Animals; Conjunctiva; Cornea; Eye Diseases; Fibroblasts; Fibrosis; Gene Transfer Techniques; Genetic Therapy; Humans; Lens Capsule, Crystalline; Mitogen-Activated Protein Kinases; Retina; Skin; Smad Proteins; Transforming Growth Factor beta

Fibrotic diseases are characterized by the appearance of myofibroblasts, the key cell type involved in the fibrogenic reaction, and by excess accumulation of extracellular matrix with resultant tissue contraction and impaired function. Myofiborblasts are generated by fibroblast-myofibrobalst conversion, and in certain tissues through epithelial-mesenchymal transition (EMT), a process through which an epithelial cell changes its phenotype to become more like a mesenchymal cell. Although inflammatory/fibrogenic growth factors/cytokines produced by injured tissues orchestrate the process of EMT, transforming growth factor beta (TGFbeta) is believed to play a central role in the process. Unlike fibrotic lesions in kidney or other tissues where myofibroblasts are generated from both fibroblasts and epithelial cells, fibrotic lesions in the eye crystalline lens are derived only from lens epithelial cells without contamination of fibroblast-derived myofibroblasts. Thus, this tissue is suitable to investigate detailed mechanisms of EMT and subsequent tissue fibrosis. EMT in retinal pigment epithelium is involved in the development of another ocular fibrotic disease, proliferative vitreoretinopathy, a fibrosis in the retina. EMT-related signal transduction cascades, i. e., TGFbeta/Smad, are a target to prevent or treat unfavorable ocular tissue fibrosis, e. g., fibrotic diseases in the crystalline lens or retina, as well as possibly in other organs.

Topics: Animals; Epithelial Cells; Extracellular Matrix; Eye Diseases; Eye Injuries; Fibrosis; Genetic Therapy; Humans; Mesoderm; Ophthalmologic Surgical Procedures; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta

The Arf tumor suppressor represents one of several genes encoded at the Cdkn2a and Cdkn2b loci in the mouse. Beyond its role blunting the growth of incipient cancer cells, the Arf gene also plays an essential role in development: its gene product, p19(Arf), is induced by Tgfβ2 in the developing eye to dampen proliferative signals from Pdgfrβ, which effect ultimately fosters the vascular remodeling required for normal vision in the mouse. Mechanisms underlying Arf induction by Tgfβ2 are not fully understood. Using the chr4(Δ70 kb/Δ70 kb) mouse, we now show that deletion of the coronary artery disease (CAD) risk interval lying upstream of the Cdkn2a/b locus represses developmentally-timed induction of Arf resulting in eye disease mimicking the persistent hyperplastic primary vitreous (PHPV) found in Arf-null mice and in children. Using mouse embryo fibroblasts, we demonstrate that Arf induction by Tgfβ is blocked in cis to the 70 kb deletion, but Arf induction by activated RAS and cell culture "shock" is not. Finally, we show that Arf induction by Tgfβ is derailed by preventing RNA polymerase II recruitment following Smad 2/3 binding to the promoter. These findings provide the first evidence that the CAD risk interval, located at a distance from Arf, acts as a cis enhancer of Tgfβ2-driven induction of Arf during development.

Topics: ADP-Ribosylation Factor 1; Animals; Coronary Artery Disease; Disease Models, Animal; DNA, Intergenic; Enhancer Elements, Genetic; Eye; Eye Diseases; Fibroblasts; Gene Deletion; Gene Expression Regulation, Developmental; Mice; Mice, Transgenic; Persistent Hyperplastic Primary Vitreous; Phenotype; Receptor, Platelet-Derived Growth Factor beta; Time Factors; Transforming Growth Factor beta

To examine the effects of a histone deacetylase inhibitor, Trichostatin A (TSA), on the behavior of macrophages and subconjunctival fibroblasts in vitro and on ocular surface inflammation and scarring in vivo using an alkali burn wound healing model.. Effects of TSA on expression of inflammation-related growth factors or collagen I were examined by real-time RT-PCR or immunoassay in mouse macrophages or human subconjunctival fibroblasts. Effects of TSA on trans forming growth factor β (TGFβ)/Smad signaling were evaluated with western blotting and/or immunocytochemistry. Alkali-burn injuries on the eyes of mice were performed with three µl of 0.5 N NaOH under general and topical anesthesia. TSA (600 µg/Kg daily) or vehicle was administered to animals via intraperitoneal (i.p.) injection. Histology and real-time RT-PCR investigations evaluated the effects of TSA on the healing process of the cornea.. TSA inhibited TGFβ 1 and vascular endothelial growth factor (VEGF) expression in macrophages, and TGFβ1 and collagen I in ocular fibroblasts. It elevated the expression of 5'-TG-3'-interacting factor (TGIF) and Smad7 in fibroblasts and blocked nuclear translocation of phospho-Smad2. Real-time PCR and immunocytochemistry studies showed that systemic administration of TSA suppressed the inflammation and fibrotic response in the stroma and accelerated epithelial healing in the alkali-burned mouse cornea.. Systemic administration of TSA reduces inflammatory and fibrotic responses in the alkali-burned mouse ocular surface in vivo. The mechanisms of action involve attenuation of Smad signal in mesenchymal cells and reduction in the activation and recruitment of macrophages. TSA has the potential to treat corneal scarring in vivo.

Topics: Animals; Burns, Chemical; Cell Movement; Cell Proliferation; Cells, Cultured; Conjunctiva; Cytokines; Eye Diseases; Fibroblasts; Fibrosis; Gene Expression Regulation; Humans; Hydroxamic Acids; Inflammation; Macrophages; Mice; Neovascularization, Pathologic; Signal Transduction; Transforming Growth Factor beta; Wound Healing

Recently, we have reported that the cytokines alpha-melanocyte-stimulating hormone (alpha-MSH) and transforming growth factor-beta2 (TGF-beta2) work in synergy to induce the activation of regulatory T (Treg) cells. When we used alpha-MSH and TGF-beta2 to generate ocular autoantigen-specific Treg cells and adoptively transferred them into mice susceptible to experimental autoimmune uveoretinitis (EAU), there was suppression in the incidence and severity of EAU. Specificity to a retinal autoantigen was required for the Treg cells to suppress EAU. When stimulated, these Treg cells produced TGF-beta1, and their production of interferon-gamma, interleukin (IL)-10, and IL-4 was suppressed. Also, the Treg cells are suppressed in their proliferative response. Our results demonstrate that alpha-MSH with TGF-beta2 induce Treg cells that can subdue a tissue-specific autoimmune response. This also promotes the possibility of using these immunomodulating cytokines to purposely induce antigen-specific Treg cells to prevent and suppress autoimmune disease.

Topics: Adoptive Transfer; alpha-MSH; Animals; Autoantigens; Autoimmune Diseases; CD4-Positive T-Lymphocytes; Cells, Cultured; Eye Diseases; Eye Proteins; Female; Immunosuppressive Agents; Interferon-gamma; Lymphokines; Mice; Retinitis; Retinol-Binding Proteins; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1; Transforming Growth Factor beta2; Uveitis

Topics: Animals; Antibodies, Monoclonal; Clinical Trials as Topic; Eye Diseases; Humans; Transforming Growth Factor beta; Transforming Growth Factor beta2

Tangential macular traction by the posterior vitreous cortex has been widely accepted as the major causative factor in the development of idiopathic macular holes. Separation of the posterior cortical vitreous should relieve this vitreoretinal traction.. The authors report five patients with idiopathic full-thickness macular hole formation that occurred in the presence of a well-documented pre-existing complete posterior vitreous detachment.. Of five eyes, three underwent pars plana vitrectomy and instillation of transforming growth factor-beta. No residual prefoveal cortical vitreous was present at the retinal surface at the time of surgery. Additionally, clinically identifiable epiretinal membranes were present in three of five eyes, but these epiretinal membranes were extremely thin, transparent, induced minimal traction, and did not warrant surgical peeling.. It is likely that, in these five patients, some mechanism other than tangential traction by prefoveal vitreous cortex is responsible for idiopathic full-thickness macular hole formation.

Topics: Aged; Aged, 80 and over; Eye Diseases; Female; Fluorescein Angiography; Follow-Up Studies; Fundus Oculi; Humans; Male; Retinal Perforations; Retrospective Studies; Transforming Growth Factor beta; Visual Acuity; Vitrectomy; Vitreous Body

The main cause of failure after retinal reattachment surgery is proliferative vitreoretinopathy (PVR), in which contractile fibrocellular membranes form on the retinal surface and vitreous base. Recently, elevated levels of transforming growth factor-beta 2 (TGF-beta 2) were measured in the vitreous of patients with PVR, suggesting a possible association with the disease. Because neutralizing TGF-beta may prove useful in controlling this blinding disease process, the authors examined the effect of anti-TGF-beta 1 and TGF-beta 2 antibodies in TGF-beta-mediated fibroblast-induced collagen gel contraction.. Rabbit dermal fibroblasts were combined with type I collagen in an in vitro model of collagen gel contraction. The authors evaluated the effect of TGF-beta 1, TGF-beta 2, and their antibodies on fibroblast-induced gel contraction.. TGF-beta 1 and TGF-beta 2 equally enhanced gel contraction to an average of 6% to 7% of the control area by day 4. In contrast, gels without TGF-beta contracted only to an average of 38% of the control gels. Several anti-TGF-beta antibodies neutralized this TGF-beta-enhanced contraction, whereas control IgGs had no effect. A dose-dependent response was detected with TGF-beta 1, TGF-beta 2, and anti-TGF-beta.. Because TGF-beta levels have been shown to correlate with the severity of PVR, the neutralizing action of anti-TGF-beta on TGF-beta-mediated contraction may offer further insights into the structure and function of PVR membranes and may provide clues to possible therapeutic solutions for controlling this disease process.

Topics: Animals; Antibodies; Cells, Cultured; Collagen; Eye Diseases; Fibroblasts; Gels; Models, Biological; Neutralization Tests; Rabbits; Retinal Diseases; Transforming Growth Factor beta; Vitreous Body

Proliferative vitreoretinopathy (PVR) involves the formation of intravitreal fibrocellular membranes which may lead to traction retinal detachment and blindness. The cellular component of epiretinal membranes originates from the proliferation and migration of cells within the eye. Several growth factors and other cytokines are plausible candidates for directing the processes leading to membrane formation. A reproducible animal model is needed for experimental studies of cytokine expression during PVR induction or treatment. We found that intravitreal injection of > 10(6) mixed mononuclear leukocytes or adherent monocytes along with a trans-scleral incision through the pars plana leads to the development of PVR-like disease in rabbit eyes. The severity of the disease was related to the number of monocytes injected. Typically, organized membranes extending from the incision toward the optic nerve formed within one week. Progression to extensive traction retinal detachment required 1 to 4 weeks. Injection of up to 5 x 10(6) lymphocytes or freeze-thaw killed monocytes was ineffective, and coinjecting 100 micrograms endotoxin with the monocytes did not result in enhanced disease. The histological appearance of the epiretinal membranes was similar to human PVR membranes. Macrophage, cytokeratin-positive (epithelial), and fibroblast-like cells were present. Northern blot analysis of RNA extracted from the rabbit membranes revealed the presence of mRNA for acidic fibroblast growth factor (aFGF). Acidic FGF mRNA was not expressed by the injected monocytes. A comparable level of aFGF mRNA and also mRNAs for basic FGF, platelet-derived growth factor-B, and transforming growth factor beta were found in epiretinal membranes induced by a scleral incision in association with cryopexy.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Disease Models, Animal; Eye Diseases; Fibroblast Growth Factor 1; Fibroblast Growth Factor 2; Growth Substances; Monocytes; Platelet-Derived Growth Factor; Rabbits; Retinal Diseases; RNA; RNA, Messenger; Transforming Growth Factor beta; Vitreous Body