Tenon's Fibroblasts Research Articles

Comparison of Six Different Silicones In Vitro for Application as Glaucoma Drainage Device.

Silicones are widely used in medical applications. In ophthalmology, glaucoma drainage devices are utilized if conservative therapies are not applicable or have failed. Long-term success of these devices is limited by failure to control intraocular pressure due to fibrous encapsulation. Therefore, different medical approved silicones were tested in vitro for cell adhesion, cell proliferation and viability of human Sclera (hSF) and human Tenon fibroblasts (hTF). The silicones were analysed also depending on the sample preparation according to the manufacturer’s instructions. The surface quality was characterized with environmental scanning electron microscope (ESEM) and water contact angle measurements. All silicones showed homogeneous smooth and hydrophobic surfaces. Cell adhesion was significantly reduced on all silicones compared to the negative control. Proliferation index and cell viability were not influenced much. For development of a new glaucoma drainage device, the silicones Silbione LSR 4330 and Silbione LSR 4350, in this study, with low cell counts for hTF and low proliferation indices for hSF, and silicone Silastic MDX4-4210, with low cell counts for hSF and low proliferation indices for hTF, have shown the best results in vitro. Due to the high cell adhesion shown on Silicone LSR 40, 40,026, this material is unsuitable.

Low density lipoprotein - rosiglitazone - chitosan-calcium alginate/nanoparticles inhibition of human tenon's fibroblasts activation and proliferation.

Anti-fibrotic therapeutic methods with safety and efficiency after glaucoma filtration surgery (GFS) are desirable. In our previous study, by using Human Tenon's Fibroblasts (HTFs) as a model, we proved the expression of peroxisome proliferator activates receptor-γ (PPAR-γ) in HTFs; in addition, rosiglitazone (RSG), an agonist of PPAR-γ, can inhibit transforming growth factorsβ1 (TGF-β1)-induced reactivation of HTFs, thus to inhibit specifically scarring after GFS through intervening TGF-β/Smads signal pathway. However, a better drug delivery way of RSG, to prolong the duration of its function, and to reduce the toxicity of RSG to ocular tissue still remains challenges. Low density lipoprotein receptor (LDLr) is strongly expressed in hyper-proliferation HTFs after GFS. Therefore, we structured targeting LDL-RSG complexes and channel them into HTFs through LDL-LDLr pathway in order to promote anti-proliferation of HTFs and reduce the toxicity to ocular tissue. Meanwhile, in order to improve the release properties of LDL-RSG complexes, we structured slow release system of LDL-RSG/chitosan-calcium alginate - nanoparticles (CSNP), which effectively inhibited TGF-β1-induced HTFs proliferation, synthesis of extracellular matrix and activation of TGF-β1/SMAD pathway. These data suggested that LDL-RSG/CSNP can be a new anti-fibrotic therapeutic method on scarring after GFS and also a novelty administration of RSG.

The Antiangiogenesis Effect of Pirfenidone in Wound Healing In Vitro.

The proliferation of human umbilical vein endothelial cells (HUVECs) and human Tenon's fibroblasts (HTFs) were detected by WST-1 assay. The cell viability of HUVECs was measured by Trypan Blue together with lactate dehydrogenase, Annexin 5 experiment, and Ki-67 immunofluorescence assay. The functions of HUVECs and HTFs were demonstrated using cell migration assay, transwell invasion assay, and tube formation assay. The expression levels of vascular endothelial growth factor-A (VEGF-A), VEGF receptor-2 (VEGFR-2), neuropilin-1(NRP-1), and their downstream signaling proteins p-PI3K, PI3K, p-AKT, AKT, p-mTOR, and mechanistic target of rapamycin (mTOR) were indicated by western blot assay. The secretion of VEGF-A was detected by enzyme-linked immunosorbent assay. Pirfenidone inhibited proliferation, migration, invasion, and tube formation of HUVECs in vitro, and had an equivalent antiangiogenesis effect when compared with Ranibizumab in HUVECs and HTFs. Pirfenidone downregulated VEGF-A/VEGFR-2, VEGF-A/NRP-1, and its downstream signaling pathway protein expression. Pirfenidone has an antiangiogenesis effect in the wound healing process and may become an ideal multitarget antiscarring agent after glaucoma filtration surgery.

Effects of docosahexaenoic acid on the viability of human tenon's fibroblasts

PurposeExcessive scarring of the conjunctiva is the major cause of failure of the surgical treatment for glaucoma. The activation of human Tenon's fibroblast (HTFs) is supposed to be responsible for wound healing and scar formation. Antimetabolites are used to inhibit subconjunctival fibrosis but these molecules may lead to serious complication. Previous studies have shown that omega‐3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) have anti‐inflammatory, anti‐proliferative and anti‐angiogenic properties. The aims of this study were to evaluate DHA as a potential inhibitor of human Tenon's fibroblasts.MethodsPrimary HTF cells were obtained from patients during glaucoma surgery and were cultured in DMEM medium. After stimulation with TGF‐β2, HTFs were treated with MMC (0.01 mg/mL) and different concentrations of DHA (50, 100 and 200 μM) for 48 hours. Lipid profile of HTFs was determined by gas chromatography, cell proliferation by Ki67 assay, cell migration was evaluated by videomicroscopy and cell toxicity by MTT assay. The expression α‐SMactin and MAPK p38, ERK, JNK in their non‐phosphorylated and phosphorylated forms was determined by western blotting.ResultsMMC reduced proliferation, migration compared to control but showed important toxicity suggested by the increased respiratory rate of mitochondrie in cytotoxicity assay and confirmed by a G2 arrest in cell cycle. DHA had no significant impact on cellular viability. DHA at 200 μM showed an efficacity similar to MMC. A reduction of the ability of cells to migrate was observed with DHA in a dose‐dependent manner. DHA efficiently dicreased α‐SMactin expression of myofibroblasts. Proteins from the Smad signaling pathway could not be observed.ConclusionsThese findings indicate that DHA inhibits migration and differentiation of HTFs to myofibroblats.

Anti-scarring effects of butaprost on human subconjunctival Tenon's fibroblasts.

To investigate the toxicity of the E-prostanoid 2 (EP2) receptor agonist, butaprost against human subconjunctival (Tenon's capsule) fibroblasts, and to determine the underlying mechanism. We isolated Tenon's fibroblasts from the subconjunctival area of healthy subjects and evaluated the types of EP receptors expressed using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). The toxicity of butaprost against the fibroblasts was evaluated using methyl thiazolyl tetrazolium and lactic dehydrogenase assays. The inhibition of conjunctival fibroblast proliferation by butaprost was assessed by measuring α-actin levels. The underlying mechanism was assessed by measuring intracellular cyclic adenosine monophosphate (cAMP) levels. Intergroup differences were statistically analyzed using an independent t-test. Densitometry of the Western blot bands was performed using the Image J software. Quantitative real-time RT-PCR revealed that the fibroblast EP2 receptor levels were higher than those of the other EP receptors. Butaprost did not show toxicity against Tenon's tissue, but inhibited conjunctival fibroblast proliferation by reducing collagen synthesis. EP2 receptor activation enhanced the cAMP cascade, which might be an important mechanism underlying this effect. Butaprost effectively reduces the subconjunctival scarring response. Given the significance of wound healing modulation in blebs, butaprost's inhibitory effect on subconjunctival Tenon's fibroblasts may be beneficial in managing postoperative scarring in glaucoma surgery.

Inhibition of Monocyte Chemoattractant Protein 1 Prevents Conjunctival Fibrosis in an Experimental Model of Glaucoma Filtration Surgery.

To evaluate the effect of treatment with monocyte chemoattractant protein-1 receptor inhibitor (MCP-Ri) to maintain bleb survival and prevent fibrosis in an experimental model of glaucoma filtration surgery (GFS). GFS was performed on one eye of C57/Bl6 mice (n = 36) that was treated with MCP-Ri, mitomycin-C (MMC), or vehicle at the time of surgery. Real-time polymerase chain reaction was used to evaluate conjunctival expression of monocyte chemoattractant protein-1 (MCP-1), TGFB1, TGFB2, collagen 1a1 (Col1a1), sparc (Sparc), and fibronectin at 2 and 7 days following surgery. Anterior segment slit-lamp examination, optical coherence tomography, and confocal microscopy were performed in vivo at day 14. Eyes were processed for immunohistochemical staining of F4/80, a monocyte-macrophage marker, at day 2. In vitro experiments were also performed to compare the effect of MMC, MCP-Ri, and vehicle on the viability of mouse Tenon's fibroblasts. Treatment with MCP-Ri results in a greater reduction in the percentage of F4/80-positive cells in conjunctival blebs and lesser MCP-1 gene expression following experimental GFS than MMC or control. Both MMC and MCP-Ri reduced Col1a1 and Sparc expression, but not fibronectin. TGFB1 decreased with MCP-Ri but not MMC; MMC but not MCP-Ri reduced TGFB2. MMC and MCP-Ri treatment resulted in the preservation of bleb height at day 14, as compared to control. MCP-Ri was less toxic to mouse Tenon's fibroblasts in comparison with MMC. Targeting MCP-1 results in prolonged bleb survival following experimental GFS with less cellular toxicity as compared to MMC. MCP inhibition could provide a safer alternative to conventional antifibrotic adjunctive treatments in GFS.

An Ilomastat-CD Eye Drop Formulation to Treat Ocular Scarring.

PurposeThe purpose of this study was to develop a topical matrix metalloproteinase inhibitor preparation for antiscarring therapy.MethodsThe broad spectrum matrix metalloproteinase inhibitor ilomastat was formulated using 2-hydroxypropyl-β-cyclodextrin in aqueous solution. In vitro activity of ilomastat-cyclodextrin (ilomastat-CD) was examined using fibroblasts seeded in collagen. Permeation of ilomastat-CD eye drop through pig eye conjunctiva was confirmed using Franz diffusion cells. Ilomastat-CD eye drop was applied to rabbit eyes in vivo, and the distribution of ilomastat in ocular tissues and fluids was determined by liquid chromatography-mass spectroscopy.ResultsThe aqueous solubility of ilomastat-CD was ∼1000 μg/mL in water and 1400 μg/mL in PBS (pH 7.4), which is greater than ilomastat alone (140 and 160 μg/mL in water and PBS, respectively). The in vitro activity of ilomastat-CD to inhibit collagen contraction in the presence of human Tenon fibroblast cells was unchanged compared to uncomplexed ilomastat. Topically administered ilomastat-CD in vivo to rabbit eyes resulted in a therapeutic concentration of ilomastat being present in the sclera and conjunctiva and within the aqueous humor.ConclusionsIlomastat-CD has the potential to be formulated as an eye drop for use as an antifibrotic, which may have implications for the prevention of scarring in many settings, for example glaucoma filtration surgery.

Pirfenidone Induces G1 Arrest in Human Tenon's Fibroblasts In Vitro Involving AKT and MAPK Signaling Pathways.

To investigate the underlying mechanism by which pirfenidone blocks the transition from the G1 to S phase in primary human Tenon's fibroblasts. Primary human Tenon's fibroblasts were characterized by immunocytofluorescence staining with vimentin, fibroblast surface protein, and cytokeratin. After treating Tenon's fibroblasts with pirfenidone under proliferation conditions (10% fetal bovine serum), cell proliferation was measured using a WST-1 assay. Progression through the cell cycle was analyzed by flow cytometry. The expression of CDK2, CDK6, cyclinD1, cyclinD3, and cyclinE and the phosphorylation of AKT, ERK1/2/MAPK, JNK/MAPK, and p38 MAPK were estimated using western blot analysis. Under proliferative conditions, pirfenidone inhibited Tenon's fibroblasts proliferation and arrested the cell cycle at the G1 phase; decreased the phosphorylation of AKT, GSK3β, ERK1/2/MAPK, and JNK/MAPK; increased the phosphorylation of p38 MAPK; and inhibited CDK2, CDK6, cyclin D1, cyclin D3, and cyclin E in a dose-dependent manner. Inhibitors of AKT (LY294002), ERK1/2 (U0126), and JNK (SP600125) arrested the G1/S transition, similar to the effect of pirfenidone. The p38 inhibitor (SB202190) decreased the G1-blocking effect of pirfenidone. The expression of CDK2, CDK6, cyclin D1, and cyclin D3 were inhibited by LY294002, U0126, and SP600125. SB202190 attenuated the pirfenidone-induced reduction of CDK2, CDK6, cyclin D1, cyclin D3, and cyclin E. Pirfenidone inhibited HTFs proliferation and induced G1 arrest by downregulating CDKs and cyclins involving the AKT/GSK3β and MAPK signaling pathways.

Losartan Attenuates Scar Formation in Filtering Bleb After Trabeculectomy.

To examine the effects of losartan on scar formation after trabeculectomy and on fibrotic changes of human Tenon's fibroblasts (HTFs). Trabeculectomy was performed on New Zealand rabbits. They were randomized to receive one of the following treatments: 0.9% normal saline, mitomycin-C, or one of the three doses of losartan. Bleb morphology, IOP, and histopathology examination were performed. Primary cultured HTFs were treated with losartan or vehicle, with or without angiotensin II (Ang II). Cell proliferation was assessed by Cell Counting Kit-8 assay, and cell migration was detected by scratch wound and transwell assay. Transdifferentiation was evaluated through the expression of α-smooth muscle actin (α-SMA) by immunofluorescence, real-time PCR, and Western blot. The expression of fibronectin (FN) was evaluated by real-time PCR and Western blot. An amount of 5 mg/mL of losartan subconjunctival injection significantly decreased IOP postoperatively and attenuated wound healing of the filtering bleb in the rabbit model. Immunostaining results showed less myofibroblast and collagen deposition around the bleb area in the losartan-treated eyes. Losartan (10-5 M) in vitro significantly attenuated Ang II's stimulatory effects on proliferation and migration of HTFs. Expressions of α-SMA and FN in these cells were also decreased by losartan pretreatment. Losartan attenuates scar formation of filtering bleb after trabeculectomy likely via decreasing proliferation, migration, transdifferentiation, and extracellular matrix deposition of Tenon's fibroblasts. These results indicate that losartan may be an effective therapeutic agent in preventing bleb scar formation and in improving surgical outcome after trabeculectomy.

The selective cysteinyl leukotriene receptor 1 (CysLT1R) antagonist montelukast regulates extracellular matrix remodeling

Scar formation after filtration surgery of glaucoma is mainly caused by excessive synthesis of new extracellular matrix (ECM) and contraction of subconjunctival tissue mediated by human Tenon fibroblasts (HTFs) and the transforming growth factor (TGF-β1). Montelukast, a potent and specific cysteinyl leukotriene receptor 1 (cysLT1R) antagonist, is a licensed drug clinically used for the treatment of bronchial asthma. In this study, we investigated the effects of montelukast on the contractility of HTFs cultured in a three-dimensional collagen gel. We found that cysLT1R was expressed in HTFs. Interestingly, the expression of cysLT1R was increased in response to TGF-β1 in a dose dependent manner, suggesting its potential role in TGF-β1 induced fibrosis. Importantly, we found that montelukast inhibited TGF-β1-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner. In addition, TGF-β1-induced expression of MMP-1 and MMP-3, generation of fibronectin and type I collagen production, focal adhesion kinase (FAK) and paxillin phosphorylation in HTFs were also ameliorated by montelukast in a dose dependent manner. These results suggested that montelukast might provide therapeutic possibilities for inhibition of scar formation after such surgery.

Suppression of Human Tenon Fibroblast Cell Proliferation by Lentivirus-Mediated VEGF Small Hairpin RNA.

Purpose. The functions of vascular endothelial growth factor (VEGF) in scar formation after trabeculectomy were investigated in a human Tenon fibroblast cell line from glaucoma patients using lentivirus-mediated VEGF shRNA. Methods. Human Tenon fibroblast (HTF) cells were isolated from scar tissue of glaucoma patients during secondary surgery. Lentivirus-VEGF-shRNA was constructed and transfected into HTF cells. Subsequently, VEGF mRNA and protein expression were analyzed using quantitative RT-PCR and western blotting, respectively, and the effects of VEGF knockdown were analyzed. The inhibition of HTF proliferation was monitored according to total cell numbers using ScanArray. Results. Both mRNA and protein levels of VEGF were reduced by lentivirus-mediated VEGF-shRNA, and proliferation of HTF cells was inhibited. Conclusions. Primary cultures of human Tenon fibroblast (HTF) were established, and proliferation was decreased following inhibition of VEGF. VEGF may be a suitable therapeutic target for reducing scar tissue formation in glaucoma patients after filtration surgery.

Silibinin Inhibits Platelet-Derived Growth Factor-Driven Cell Proliferation via Downregulation of N-Glycosylation in Human Tenon's Fibroblasts in a Proteasome-Dependent Manner.

The objective of this study was to evaluate the effects of silibinin on cell proliferation in platelet-derived growth factor (PDGF)-treated human Tenon's fibroblasts (HTFs). The effect of silibinin on cell proliferation in PDGF-treated HTFs was determined by examining the expression of proliferating cell nuclear antigen (PCNA) and performing WST-1 assays. Cell cycle progression was evaluated using flow cytometry. The related cyclins and cyclin-dependent kinases (CDKs) were also analyzed using western blot. A modified rat trabeculectomy model was established to evaluate the effect of silibinin on cell proliferation in vivo. Western blot analysis was carried out to determine the effect of silibinin on the expression of PDGF receptor and on the downstream signaling pathways regulated by PDGF receptor. PDGF elevated the expression of PCNA in HTFs, and this elevation was inhibited by silibinin. The inhibitory effect of silibinin on cell proliferation was also confirmed via WST-1 assay. PDGF-stimulated cell cycle in HTFs was delayed by silibinin, and the related cyclin D1 and CDK4 were also suppressed by silibinin. In the rat model of trabeculectomy, silibinin reduced the expression of PCNA at the site of blebs in vivo. The effects of silibinin on PDGF-stimulated HTFs were mediated via the downregulation of PDGF receptor-regulated signaling pathways, such as ERKs and STATs, which may be partially caused by the downregulation of N-glycosylation of PDGF receptor beta (PDGFRβ). The effect of silibinin on modulation of N-glycosylation of PDGFRβ was mediated in a proteasome-dependent manner. Silibinin inhibited cell proliferation and delayed cell cycle progression in PDGF-treated HTFs in vitro. PDGF also modulated the process of N-glycosylation of the PDGFRβ in a proteasome-dependent manner. Our findings suggest that silibinin has potential therapeutic applications in glaucoma filtering surgery.

The Antiproliferative Effect of Bevacizumab on Human Tenon Fibroblasts Is Not Mediated by Vascular Endothelial Growth Factor Inhibition.

Vascular endothelial growth factor-signaling in human tenon fibroblasts (hTFs) has recently become a target for antifibrotic treatment in glaucoma filtration surgery. The anti-VEGF antibody bevacizumab (BVC) has been shown to increase filtration bleb size. Given the relatively high concentration of BVC needed to obtain an effect, we investigated whether BVC acts through VEGF inhibition or via non-antigen-dependent ways. Human tenon fibroblast primary cultures were obtained from strabismus surgery subjects. Under low (0.2%) and high (10%) serum conditions, cells were incubated with BVC, ranibizumab (RNB), aflibercept (AFB), or rituximab (RTX) at different concentrations. Total number of cells and number of dead or proliferating (5-bromo-2-deoxy-uridine-positive) cells were assessed after 24 hours. Concentrations of VEGF-A in cell culture media was measured with ELISA. Intracellular IgG was detected with immunostaining and Western blot analysis. In quiescent hTF culture (0.2% serum) the addition of 5 mg/mL BVC induced widespread cell death. Under proliferative conditions (10% serum), BVC reduced the number of proliferating cells. No such effect was observed with 2.5 mg/mL BVC or with 10 mg/mL AFB or 2.5 mg/mL RNB, although they were equally effective in binding free VEGF-A in the culture media. Instead, the CD20 antibody RTX, which did not bind VEGF, induced hTF death and inhibited proliferation in a BVC-comparable fashion. Bevacizumab, AFB, and RTX were detected intracellularly in a concentration-dependent manner. The cell death-inducing and antiproliferative effect of 5 mg/mL BVC appeared not to depend on VEGF inhibition. Our data question a direct role of VEGF for hTF survival and proliferation.

Tetramethylpyrazine Attenuates Transdifferentiation of TGF-β2–Treated Human Tenon's Fibroblasts

To investigate the pharmacologic effect of tetramethylpyrazine (TMP) on human Tenon's fibroblasts (HTFs), the cells implicated in scarring after filtration surgery. Transforming growth factor-β2 (TGF-β2) was used to stimulate a fibrotic phenotype in primary HTFs, and the influence of TMP on the fibrotic phenotype was assessed. Cell proliferation and cell cycle regulation were profiled. Immunofluorescence staining tracked proliferating cell nuclear antigen (PCNA) expression. Transwell assays monitored cell migration. Flow cytometry measured TMP toxicity. In addition, in TGF-β2-treated HTFs, Western blot and immunofluorescence were employed to assess the expression of α-smooth muscle actin (α-SMA). The TMP-mediated activity on cytoskeletal arrangements and extracellular matrix (ECM) accumulation in HTFs was evaluated using actin polymerization and Western blot assays. Moreover, TGF-β-dependent activation of Smad3 and p38 was examined by Western blot analysis. In TGF-β2-treated HTFs, TMP reduced proliferation and migration but did not induce apoptosis. Moreover, TMP attenuated expression of α-SMA and suppressed stress fiber formation stimulated by profibrotic cytokine; it also counteracted TGF-β2-induced cytoskeletal rearrangements, morphologic changes, and ECM accumulation. Smad3 and p38 mitogen-activated protein kinase (MAPK) signaling were downstream of the TMP-sensitive effect. Tetramethylpyrazine counteracts TGF-β2-mediated myofibroblast transdifferentiation and attenuates ECM component deposition and cell proliferation in HTFs, implicating TMP as a potential antifibrosis agent in glaucoma filtration surgery.

Development of a novel CsA-PLGA drug delivery system based on a glaucoma drainage device for the prevention of postoperative fibrosis

The formation of a scar after glaucoma surgery often leads to unsuccessful control of intraocular pressure, and should be prevented by using a variety of methods. We designed and developed a novel drug delivery system (DDS) comprising cyclosporine A (CsA) and poly(lactic-co-glycolic acid) (PLGA) based on a glaucoma drainage device (GDD) that can continuously release CsA to prevent postoperative fibrosis following glaucoma surgery. The CsA@PLGA@GDD DDS was observed by field emission scanning electron microscopy and revealed an asymmetric pore structure. Thermogravimetric analysis was performed to measure the weight loss and evaluate the thermal stability of the CsA@PLGA@GDD DDS. The in vitro drug release profile of the DDS was studied using high performance liquid chromatography, which confirmed that the DDS released CsA at a stable rate and maintained adequate CsA concentrations for a relatively long time. The biocompatibility of the DDS and the inhibitory effects on the postoperative fibrosis were investigated in vitro using rabbit Tenon's fibroblasts. The in vivo safety and efficacy of the DDS were examined by implanting the DDS into Tenon's capsules in New Zealand rabbits. Bleb morphology, intraocular pressure, anterior chamber reactions, and anterior chamber angiography were studied at a series of set times. The DDS kept the filtration pathway unblocked for a longer time compared with the control GDD. The results indicate that the CsA@PLGA@GDD DDS represents a safe and effective strategy for preventing scar formation after glaucoma surgery.

Paclitaxel inhibits cell proliferation and collagen lattice contraction via TGF-β signaling pathway in human tenon's fibroblasts in vitro

As an anti-microtubule agent, paclitaxel has been widely applied clinically. However, the effects of paclitaxel on human tenon's fibroblast (HTF) proliferation and migration in vitro was still unclear. In the present study, we explored the influences of paclitaxel on HTF cell proliferation, cell viability, cell cycle phase distribution under various concentrations of paclitaxel (i.e., 0, 10−8, 10−7, 10−6mol/l) via real-time cell electronic system and flow cytometry, further determined the expression of TGF-β1 and connective tissue growth factor (CTGF) after treatment with different concentrations of paclitaxel. Moreover, extra cellular matrix production and collagen lattice contraction assay were also explored. The results indicate that paclitaxel could apparently inhibit the cell viability, induces the elevation of S and G2/M phases of HTFs, and downregulates the expression of both TGF-β1 and CTGF. Meanwhile, the levels of fibronectin extra domain A (EDA), collagen and collagen lattice contraction were apparently reduced after treatment with paclitaxel. Overall, paclitaxel could apparently inhibit the proliferation of HTFs and leads to cell cycle arrest at both S and G2/M phases, attenuates the generation of collagen and collagen lattice contraction, decreases the expressions of TGF-β1, CTGF and fibronectin EDA. The inhibitory mechanism of paclitaxel on HTFs is involved in TGF-β1 signaling pathway.

GMP-grade platelet lysate enhances proliferation and migration of tenon fibroblasts.

Tenon's fibroblasts (TFs), widely employed as in vitro model for many ophthalmological studies, are routinely cultured with FBS. Platelet Lysate (PL), a hemoderivate enriched with growth factors and cytokines has been largely tested in several clinical applications and as substitute of FBS in culture. Here, we investigate whether PL can exert biological effects on TF populations similarly to other cell types. Results show that PL significantly enhances cell proliferation and migration vs. FBS, without influencing cell size/granularity. Upregulation of EGF, VEGF, KDR, MMP2-9, FAK mRNA levels also occurs and phosphorylation of AKT but not of ERK1/2 is significantly enhanced. The inhibition of the PI3kinase/AKT pathway with the specific inhibitor wortmannin, decreases PL-induced cell migration but not proliferation. Condition supernatants containing PL show increased bioavailability of Nitric Oxide and reduced levels of 8-Iso-PGF2-alpha, correlating with cell proliferation and migration. Pro-angiogenic/inflammatory soluble factors (GRO, Angiogenin, EGF, I-309, PARC) are exclusively or greater expressed in media containing PL than FBS. GMP-grade PL preparations positively influence in vitro biological effects of TFs representing a suitable and safer alternative to FBS.

GMP-grade platelet lysate enhances proliferation and migration of tenon fibroblasts

GMP-grade platelet lysate enhances proliferation and migration of tenon fibroblasts

In vitro characteristics of Tenon's fibroblast lines derived from pediatric and adult eyes do not fully explain pediatric glaucoma surgery failure: a preliminary report

To compare the in vitro characteristics of Tenon's capsule fibroblasts from children and adults that may be relevant to filtration surgery success. Fibroblast cell lines derived from 5 young (median patient age, 2.4 years) and 7 old (median patient age, 71 years) discarded Tenon's capsule surgical specimens were used at early passage (P2-P3). Fibroblasts were plated at "high" (10(4)cells/cm(2)) or "low" density (10(3)cells/cm(2)) and harvested at days 0-14, for growth curve and doubling time comparisons. Migration was measured using a wound model (confluent monolayers ± 5-fluorouracil [5-FU] over 1-96 hours). Collagen synthesis was measured as secreted hydroxyproline/24 hours from confluent monolayers. At low density, "young" fibroblasts achieved higher cell numbers at confluence (day 14) compared with "old": 158 ± 35 versus 105 ± 12 × 10(3)cells/cm(2) (P = 0.0034). Mean doubling time for young versus old was similar at low density plating: 20.95 ± 1.55 versus 22.37 ± 2.09 hours (P = 0.26). It was shorter, however, for young versus old at high-density plating: 42.11 ± 6.01 versus 54.26 ± 4.24 hours (P = 0.0051). Wound closure rates were similar for young versus old cells (4 lines for each group) with and without 5-FU. Collagen synthesis was similar for young and old (4 lines for each group). Although young fibroblasts reached higher density than old at confluence and had shorter doubling times at high-density plating, wound closure/migration and collagen synthesis rates were similar. Despite the preliminary nature of this study (few specimens, limited cell features explored), factors besides those intrinsic to the fibroblasts themselves likely mediate the more rapid healing/scarring after glaucoma filtration surgery in children.

Downregulating the Myocardin‐related transcription factor/ Serum response factor (MRTF/SRF) pathway is a novel therapeutic approach to prevent post‐surgical fibrosis in glaucoma

PurposeGlaucoma is the first leading cause of irreversible blindness worldwide and fibrosis is the main cause of failure of glaucoma surgery. There are currently no available anti‐fibrotic treatments in the eye. We have previously described how the MRTF/SRF transcription pathway is intricately linked to all the key pathways in ocular fibrosis. We thus hypothesised that inhibiting the MRTF/SRF pathway would be a good therapeutic target to prevent fibrosis in the eye.MethodsMRTF and SRF expression were knocked down in human Tenon's fibroblasts using small interfering RNAs, and three‐dimensional fibroblast‐populated collagen gels were used to measure contraction in vitro. Cytotoxicity was assessed using the live‐dead assay. Live cell imaging was used to study the cell protrusive behaviour during contraction and quantification was performed using a custom parameter, the dynamic index. Reflection confocal microscopy and DQ collagen were also used to measure matrix degradation. Real‐time qPCR was used to compare the gene expression of key matrix metalloproteinases in contracting gels.ResultsMRTF and SRF silencing significantly decreased collagen matrix contraction by 80% and 87% respectively. MRTF silencing did not impair cell viability compared to controls. Knocking down MRTF markedly reduced the protrusive behaviour of human Tenon's fibroblasts (dynamic index = 0.19 as compared to 0.66 for controls). MRTF silencing also significantly decreased matrix degradation and the expression of MMP‐1, MMP‐2, MMP‐9, and MMP‐14 genes.ConclusionsOur study is the first to show that inhibiting the MRTF/SRF pathway significantly decreases collagen matrix contraction, cell protrusive behaviour of fibroblasts, and matrix degradation in the conjunctiva, and thus represents a promising new therapeutic approach to prevent post‐surgical fibrosis in glaucoma.