Proliferative response of cultured human tenon's capsule fibroblasts to platelet-derived growth factor isoforms

Predominant control of PDGF/PDGF receptor signaling in the migration and proliferation of human adipose‑derived stem cells under culture conditions with a combination of growth factors

Human adipose-derived stem cells (hASCs) play important roles in regenerative medicine and tissue engineering. However, their clinical applications are limited because of their instability during cell culture. Platelet lysates (PLTs) contain large amounts of growth factors that are useful for manufacturing cellular products. Platelet-derived growth factor (PDGF) is a major growth factor in PLTs and a potent mitogen in hASCs. To optimize growth conditions, the effects of a combination of growth factors on the promotion of hASC proliferation were investigated. Moreover, PDGF-BB combined with vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) markedly enhanced the viability of hASCs compared with the effects of PDGF-BB alone. Neither VEGF nor HGF had any effect alone. All growth factor receptor inhibitors inhibited cell proliferation. Wound healing assays revealed that VEGF and HGF stimulated PDGF-dependent cell migration. The effects of these growth factors on the activation of their cognate receptors and signaling enzymes were assessed using immunoblotting. Phosphorylation of PDGF receptor (PDGFR)β, VEGF receptor (VEGFR)2 and MET proto-oncogene and receptor tyrosine kinase was induced by PDGF-BB treatment, and was further increased by treatment with PDGF-BB/VEGF and PDGF-BB/HGF. The levels of phospho-ERK1/2 and phospho-p38MAPK were increased by these treatments in parallel. Furthermore, the expression levels of SRY-box transcription factor 2 and peroxisome proliferator-activated receptor g were increased in PDGF-BB-treated cells, and PDGF-BB played a dominant role in spheroid formation. The findings of the present study highlighted that PDGF/PDGFR signaling played a predominant role in the proliferation and migration of hASCs, and suggested that PDGF was responsible for the efficacy of other growth factors when hASCs were cultured with PLTs.

Statin use and the reoperation rates in glaucoma filtration surgery - population-based cohort study

PURPOSE

To examine the association of systemic statin therapy and reoperation rate after glaucoma filtration surgery (GFS).

METHODS

This is a population-based, historic cohort study of 2705 eyes undergoing GFS in Finland between July 2009 and December 2016. GFSs were identified from national administrative healthcare registers. Baseline sociodemographic and health characteristics were documented. Reoperation rates of GFS subgroups were analysed, with statin users compared to non-users. The outcomes were modelled using a Poisson regression model adjusted for age, sex, education, statin use, chronic comorbidities, and cataract surgery with incident rate ratios (IRR) as the main outcome measure.

RESULTS

The cohort contained 2263 subjects with open-angle glaucoma (OAG), 823 men and 1440 women. Surgery was performed on 2705 eyes. First documented procedures: deep sclerectomy (DS) (n = 1601), trabeculectomy (TRE) (799) and glaucoma drainage device (GDD) implantation (305) respectively. In total, 438 secondary operations were performed during the 7.5-year (median 2.25 years) follow-up period. The reoperation rates were 19% after DS, 12% after TRE, and 13% after GDD. Of the surgical procedures, 32% were performed on eyes of patients receiving statin therapy. Statin users showed no difference in reoperation rates (IRR 1.06, CI 0.82-1.37). In subgroups, no difference was observed in the reoperation rates adjusted with statin use after filtration surgery (DS, TRE) (IRR 1.06, CI 0.8-1.40) or GDD implantation (0.57, CI 0.20-1.63).

CONCLUSION

Systemic statin therapy among surgically treated OAG patients had no impact on secondary surgery rates following DS, TRE or GDD implantation.

Effects of Regorafenib, a Multi-Kinase Inhibitor, on Conjunctival Scarring in a Canine Filtration Surgery Model in Comparison with Mitomycin-C

Regorafenib eye drops were developed for treating age-related macular degeneration. This study aimed to investigate the effects of this multi-kinase inhibitor on intraocular pressure (IOP), bleb formation, and conjunctival changes in a canine filtration surgery model. Glaucoma filtration surgery models were created in 24 eyes of 24 beagles. In experiment 1 (Ex 1), regorafenib eye drops (regorafenib group: n = 6) or a vehicle (control group, n = 6) were instilled twice daily for 4 weeks postoperatively. In experiment 2 (Ex 2), regorafenib eye drops were instilled as in Ex 1 (regorafenib group: n = 6) for 12 weeks while conventional intraoperative mitomycin-C (MMC) was utilized (MMC group: n = 6), In Ex 1, only the regorafenib group showed significant IOP reduction with a significantly higher bleb score. Subconjunctival area, collagen density, vessels, and cells showing proliferation and differentiation were lower in subconjunctival tissue in the regorafenib group. In Ex 2, no significant difference was found in IOP reduction and bleb formation between the regorafenib and MMC groups; bleb walls were significantly thicker and collagen density and vessels were higher in the regorafenib group; and no differences were observed in the above-mentioned cells. Thus, regorafenib might be a better alternative to MMC for creating thicker and less ischemic blebs in glaucoma filtration surgery.

Modulation of Fibroblasts in Conjunctival Wound Healing

Modulating conjunctival wound healing has the potential to improve outcomes after glaucoma filtration surgery and for several ocular disorders, including ocular cicatrial pemphigoid, vernal keratoconjunctivitis, and pterygium. Although anti-inflammatories and antimetabolites have been used with success, these nonspecific agents are not without their complications. The search for novel and more targeted means to control conjunctival fibrosis without such limitations has brought much attention to the regulation of fibroblast proliferation, differentiation, extracellular matrix production, and apoptosis. This review provides an update on where we stand with current antifibrotic agents and outlines the strategies that novel agents use, as they evolve from the bench to the bedside.

Modulation of wound healing in glaucoma surgery

Glaucoma is a neurodegenerative disease and is the second most important cause of irreversible blindness. Filtration surgery remains the most effective therapy to reduce intraocular pressure in glaucoma patients. The main determinant of long-term surgical success is the healing response. Excessive postoperative wound healing with subsequent fibrosis may lead to obstruction of the created channel which frequently results in early surgical failure and consequent progression of visual field loss. Preoperative use of antimitotics, such as mitomycin-C and 5-fluorouracyl, effectively improves surgery outcome. However, the use of these nonspecific antiproliferative agents can be associated with severe side effects. This review provides an overview of the most important efforts that have been made to explore novel, more specific, and safer agents to prevent glaucoma filtration failure and improve surgery outcome.

Effects of epidermal growth factor, platelet derived growth factor and growth hormone on cultured rat keratinocytes cells in vitro

Some growth factors, such as Epidermal Growth Factor (EGF), Growth Hormone (GH) and Platelet Derived Growth Factor (PDGF) have beneficial effects on keratinocyte proliferation and wound healing. Although the mechanism of these factors is unclear. In response to injury, growth factors are secreted by kinds of cutaneous cells. The goal of this project is to investigate the factors that could cause proliferate of the keratinocyte cells in vitro. The keratinocytes were removed from rat pups (10 days). Cultured in media with different concentration of GH, PDGF and EGF separately. The proliferation of cells was evaluated by the method of MTT and 3H-thymidine incorporation. Proliferation of keratinocytes was significantly higher in experimental groups than in control group. EGF maximally stimulated at 10 and 25 ng mL(-1). PDGF-BB maximally stimulated at 50 ng mL(-1), respectively. And maximal stimulation of GH was 2.5 IU L(-1). GH, PDGF-BB and EGF stimulate keratinocyte cells proliferation in different concentration. These growth factors could play in healing of the skin.

The Suppression of Wound Healing Response with Sirolimus and Sunitinib Following Experimental Trabeculectomy in a Rabbit Model

PURPOSE

To investigate the effects of sirolimus and sunitinib on wound healing in experimental glaucoma filtering surgery (GFS).

MATERIAL AND METHODS

Thirty-five male New Zealand pigmented rabbits were randomly assigned to five groups, each including seven rabbits: The rabbits in the control group were not operated on and did not receive any treatment. The rabbits in the sham group underwent trabeculectomy and had one drop of saline instilled four times a day for 14 days. The rabbits in the mitomycin-C (MMC) group underwent trabeculectomy, and a sponge soaked in 0.4 mg/mL MMC was applied intraoperatively to the scleral surgical site for three minutes. The rabbits in the sirolimus group underwent trabeculectomy and 30 ng/mL sirolimus-soaked sponge was applied intraoperatively to the scleral surgical site for three minutes. Sunitinib 0.5 mg/mL four drops in a day were applied in the sunitinib group for 14 days after surgery. On day 14 of the experiment, eyes were enucleated and histologically and immunohistochemically analyzed. Statistical analyses of the study were performed with Kruskal-Wallis variance analysis and Mann-Whitney U test.

RESULTS

The mean fibroblast and MNC numbers and the mean immunostaining intensities of transforming growth factor-β (TGF-β), fibroblast growth factor-β (FGF-β) and platelet derived growth factor (PDGF) in the MMC, sirolimus and sunitinib groups were statistically significantly lower than those of the sham group (p < 0.01). The mean fibroblast and MNC numbers and the mean immunostaining intensities of TGF-β, FGF-β and PDGF in the MMC, sirolimus and sunitinib groups were similar (p > 0.05).

CONCLUSIONS

Our study suggests that the applications of sirolimus and sunitinib effectively suppress the subconjunctival scarring after experimental GFS.

Impact of trastuzumab on wound healing in experimental glaucoma surgery

BACKGROUND

To investigate the effects of subconjunctivally administered trastuzumab on wound healing in experimental glaucoma filtration surgery.

DESIGN

Comparative, experimental study.

SAMPLES

Twenty eight eyes.

METHODS

Twenty-eight male New Zealand white rabbits were randomly assigned to four groups, each including seven rabbits: The rabbits in the control group were not operated on and did not receive any treatment. The rabbits in the sham group underwent trabeculectomy and had one drop of saline instilled four times a day for 14 days. The rabbits in the mitomycin-C group underwent trabeculectomy, and a sponge soaked in 0.4 mg/mL mitomycin-C was applied intraoperatively to the scleral surgical site for 3 min. The rabbits in the trastuzumab group underwent trabeculectomy and were injected subconjunctivally once with 1.2 mg/0.1 mL of the drug. On day 14 of the experiment, the operated and control eyes were enucleated and immunohistochemically analyzed.

MAIN OUTCOME MEASURES

Mean values of fibroblast, mononuclear cell and immunostaining intensities of the transforming growth factor-β, fibroblast growth factor-β, and platelet derived growth factor.

RESULTS

The mean cell numbers and immunostaining intensities in the sham group were higher than those of the control group (P < 0.01). The mean cell numbers and immunostaining intensities in the mitomycin-C group and trastuzumab group were statistically significantly lower than those of the sham group (P < 0.01) while mean cell numbers and immunostaining intensities in the mitomycin-C group and trastuzumab group were similar (P > 0.05).

CONCLUSION

Subconjunctival trastuzumab injection effectively suppressed subconjunctival scarring after experimental glaucoma filtration surgery.

Topical infliximab for the suppression of wound healing following experimental glaucoma filtration surgery

Background

The purpose of this work was to look into the effects of infliximab on wound healing in experimental glaucoma filtration surgery and to compare the antifibrotic effects of this agent to that of mitomycin-C (MMC).

Methods

Twenty-eight male New Zealand White rabbits were randomly assigned to four groups, each including seven rabbits: control group, sham group, MMC group, and infliximab group. The rabbits in the control group were not operated on and did not receive any treatment. The rabbits in the sham group underwent trabeculectomy and had one drop of saline instilled four times a day for 14 days. The rabbits in the MMC treatment group underwent trabeculectomy, and a sponge soaked in 0.4 mg/mL MMC was applied intraoperatively to the scleral surgical site for three minutes. The rabbits in the infliximab treatment group underwent trabeculectomy and one drop of 10 mg/mL infliximab was instilled four times a day for 14 days after surgery. On day 14 of the experiment, the operated and control eyes were enucleated and histologically and immunohistochemically analyzed.

Results

The mean fibroblast and mononuclear cell (MNC) numbers and the mean immunostaining intensities of transforming growth factor-β (TGF-β), fibroblast growth factor-β (FGF-β), and platelet-derived growth factor (PDGF) in the sham group were higher than those of the control group (P<0.01). The mean fibroblast and MNC numbers and the mean immunostaining intensities of TGF-β, FGF-β, and PDGF in the MMC and infliximab groups were statistically significantly lower than those of the sham group (P<0.01). The mean fibroblast and MNC numbers and the mean TGF-β, FGF-β, and PDGF immunostaining intensities of the MMC and infliximab groups were similar (P>0.05).

Conclusion

Our study suggests that topical infliximab effectively suppresses the subconjunctival wound healing response after experimental glaucoma filtration surgery, reducing the MNC and fibroblast numbers and immunostaining intensities of TGF-β, FGF-β, and PDGF.

Improving patient outcomes following glaucoma surgery: state of the art and future perspectives

Of all the treatments currently used to lower intraocular pressure in glaucoma patients, filtration surgery is known to be the most effective. However, in a significant percentage of cases, the constructed channel closes due to excessive scar formation, resulting in surgical failure. The process of postoperative wound healing is characterized by the coagulative and inflammatory phase, followed by the proliferative and repair phase, and finally the remodeling phase. Perioperative antimitotic agents, such as mitomycin C and 5-fluorouracil, are known to modulate the process of wound healing and to improve surgical outcome, but they carry a risk of vision-threatening complications. New alternative strategies to prevent filtration failure, such as inhibition of transforming growth factor-β, vascular endothelial growth factor, and placental growth factor, have shown promising results in the improvement of surgical success. However, it remains necessary to broaden the therapeutic approach by focusing on combined therapies and on extended drug delivery.

Prevention of ocular scarring post glaucoma filtration surgery using the inflammatory cell and platelet binding modulator saratin in a rabbit model

Clinical Relevance

Late complications can occur with use of current antimetabolites to prevent scarring following glaucoma filtration surgery (GFS). Safer, more targeted, anti-fibrosis agents are sought.

Objectives

The protein saratin has been shown to exhibit anti-fibrotic and anti-thrombotic properties in response to injury, but had not been used for glaucoma surgery. The goal of this study was to compare the efficacy of saratin with that of the widely accepted mitomycin-C (MMC) in prolonging bleb survival following GFS in the rabbit model. Two saratin delivery routes were compared; a single intraoperative topical application versus a combination of intraoperative topical application with two additional postoperative injections.

Methods

Twenty-four New Zealand White rabbits underwent GFS and received either intraoperative topical saratin, intraoperative topical saratin plus two injections on post-operative days 4 and 8, balanced saline solution (BSS), or MMC. The bleb tissues and their elevation durations were compared based on clinical and histological findings.

Results

Rabbits receiving topical+injections of saratin had a mean bleb survival of 33.6±8.5 days, significantly higher than the negative BSS controls, which averaged 17.4±6.0 days (p = 0.018). No improvement over BSS was seen for rabbits receiving topical saratin only (15.5±4.8 days, p = 0.749). Rabbits receiving saratin did not develop bleb avascularity and thinning associated with MMC treatment and there were no apparent clinical signs of toxicity.

Conclusions

Treatment with a single intraoperative topical application plus two additional postoperative injections significantly prolonged bleb elevation comparable to MMC, but without toxicity; however, topical application alone was ineffective.

The role of interleukin-1beta and platelet-derived growth factor-AB in antifibrosis mediated by native human interferon alpha

BACKGROUND

Commercial preparations of native human interferon alpha (nHuIFN-alpha) contain several subtypes of interferon-alpha (IFN-alpha) and traces of other cytokines. Recently, we described its antifibrotic potential and showed nHuIFN-alpha to have a greater effect than that of recombinant human IFN-alpha (rHuIFN-alpha). We hypothesized that cooperation between different cytokines in the nHuIFN-alpha preparation is essential for this effect. Considerable concentrations of interleukin-1beta (IL-1beta) and platelet-derived growth factor AB (PDGF-AB) are present in the nHuIFN-alpha preparations.

METHODS

We tested the viability and the expression of procollagen type I messenger RNA (mRNA) in MRC5 fibroblasts treated with interleukin-1 beta (IL-1beta) and/or PDGF-AB, or the corresponding antibodies in combination with rHuIFN-alpha or nHuIFN-alpha.

RESULTS

We showed that neither IL-1beta nor PDGF-AB significantly affect the viability of MRC5 cells. Furthermore, cell viability was not affected when IL-1beta or PDGF-AB were applied along with rHuIFN-alpha, relative to the viability of cells treated with rHuIFN-alpha only. In contrast, both cytokines suppressed the synthesis of procollagen type I mRNA. When coadministered with rHuIFN-alpha, IL-1beta enhanced the suppression induced by rHuIFN-alpha. Conversely, PDGF-AB acted as an antagonist of rHuIFN-alpha and restored partially the synthesis of procollagen type I mRNA. Interestingly, the addition of IL-1beta to the PDGF-AB/rHuIFN-alpha mix not only abolished the antagonistic activity of PDGF-AB but also decreased the synthesis of procollagen type I mRNA beyond the level achieved by IL-1beta/rHuIFN-alpha. Therefore, IL-1beta was able to reverse the activity of PDGF-AB.

CONCLUSION

Our study suggests that IL-1beta is an important component of nHuIFN-alpha preparations, acting directly and indirectly to modulate the action of other components. This study provides insight into these complex cytokine networks, which is necessary for better and safer antifibrotic therapy.

Effect of diabetes mellitus and hyperglycemia on the proliferation of human Tenon's capsule fibroblasts: implications for wound healing after glaucoma drainage surgery

Glaucoma drainage surgery in diabetic patients is associated with a relatively poor prognosis due to increased scarring at the site of surgery, secondary to increased proliferation of human Tenon's capsule fibroblasts (hTCF). This is in marked contrast to diabetic wound healing at other sites, where it is generally impaired. The aim of this study was to determine why diabetics show an increased ocular scarring response in comparison to that found at other sites. Under normoglycemic conditions, hTCF isolated from diabetics showed a mean reduction in short-term proliferation (95% CI) of 45 +/- 12% compared with normal controls (p < 0.001). Under hyperglycemic conditions, proliferation of diabetic hTCF was reduced by 21 +/- 11% (p < 0.01) compared with nondiabetic controls. When exposed to transforming growth factor-beta2 (1-10,000 pg/ml) and platelet-derived growth factor-BB (0.5-500 ng/ml) under both normo- and hyperglycemic conditions, there was a dose-related increase in proliferation of both diabetic and nondiabetic controls. There was no significant difference in response to cytokine stimulation between the two groups at any of the cytokine concentrations used. Western blot analysis did not show any apparent difference in the expression of platelet-derived growth factor receptor alpha, mitogen-activated protein kinase/ERK2, or transforming growth factor-beta receptor II to account for the reduced proliferation of diabetic hTCF. These results suggest that hTCF behave in a manner similar to fibroblasts from other nonocular sites and that the increased proliferation and scarring response found in vivo may be secondary to the previously noted elevated cytokine concentrations in the aqueous and vitreous of diabetics.

Effects of octreotide acetate and amniotic membrane on wound healing in experimental glaucoma surgery

Wound healing affects the success of glaucoma filtering surgery. Antimetabolites and antifibrotic agents are used in the modulation of surgical trauma. This study is performed to evaluate the effects of amniotic membrane and octreotide acetate on wound healing. Thirty pigmented rabbits were divided into three groups each including 10 animals. Trabeculectomy and topical postoperative prednisolone sodium phosphate four times daily for 7 days were applied to one eye of all the rabbits. After trabeculectomy, octreotide 10 microg three times daily applied topically to the octreotide group for 14 days and amniotic membrane transplantation was performed by suturing amniotic membrane between scleral flap and sclera to the amniotic membrane group. The operated eyes of the rabbits were enucleated on the 14th day of the operation and histopathological specimens were obtained from the bleb sites and they were evaluated by light microscope. Fibroblast and macrophage number per cm2 were counted and the average values were calculated. Compared with the control group, the fibroblasts and macrophages significantly decreased in the other two groups (p < 0.0001, p < 0.0001, respectively). The mean number of fibroblasts was lower than those of the control and amniotic membrane groups (p < 0.0001, p < 0.0001, respectively). Similarly the mean macrophage number was significantly lower in the octreotide group versus the control and amniotic membrane groups (p < 0.0001, p < 0.01, respectively). Octreotide administration and amniotic membrane transplantation might be alternative treatments in modulating the wound healing after trabeculectomy.

Effects of growth factors (EGF, PDGF-BB and TGF-beta 1) on cultured equine epithelial cells and keratocytes: implications for wound healing

OBJECTIVE

The physiologic mechanisms involving growth factors, including PDGF-BB, EGF, and TGF-beta 1, as potent mediators of fibroblasts and epithelial cells in corneal wound healing remain unknown. The goal of this study was to determine culture methods for equine epithelial cells and keratocytes and to investigate how exogenous growth factors influence proliferation of both cell types.

PROCEDURES

Cell cultures were established from healthy corneas harvested from horses immediately following euthanasia and maintained using standard tissue culture protocols. To determine the effects of PDGF-BB, EGF, TGF-beta 1, keratocytes (1 x 10(5)/well) and epithelial cells (2 x 10(5)/well) were each cultured in 12 well plates and exposed separately to the growth factors. The cells were exposed to concentrations of EGF between 0 and 50 ng/mL; PDGF-BB between 0 and 75 ng/mL; and TGF-beta 1 between 0 and 10 ng/mL. Cell proliferation was measured using 3H-thymidine assay and differences in growth determined using anova and Tukey's HSD test (P < 0.05).

RESULTS

Epithelial cell and keratocyte cultures were successfully established. EGF maximally stimulated keratocyte and epithelial cells at 25 ng/mL and 5 ng/mL, respectively. PDGF-BB maximally stimulated keratocytes and epithelial cells at 50 ng/mL and 5 ng/mL, respectively. TGF-beta 1 inhibited keratocytes at 5 ng/mL and 10 ng/mL, and epithelial cells at 1 ng/mL and 2 ng/mL.

CONCLUSIONS

Methods were established to maintain epithelial cells and keratocytes in vitro. PDGF-BB and EGF stimulate, while TGF-beta 1 inhibits the proliferation of epithelial cells and keratocytes. These growth factors may play a role in maintenance and repair of the equine cornea.

Effect of cytokines on regulation of the production of transforming growth factor beta-1 in cultured human Tenon's capsule fibroblasts

PURPOSE

Transforming growth factor-beta1 (TGF-beta1) is thought to play a pivotal role in the regulation of the wound healing process after glaucoma filtering surgery. The aim of the present study was to investigate whether platelet-derived growth factor isoforms (PDGF-AA, PDGF-BB), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) modulate the production of latent and/or active TGF-beta1 by cultured human Tenon's capsule fibroblasts (HTF).

METHODS

Human Tenon's capsule fibroblasts were seeded at two different densities (30 cells/mm2 and 150 cells/mm2) and stimulated for five days with PDGF-AA, PDGF-BB, bFGF, EGF, IL-1beta and TGF-beta1. Control cells were treated with serum-free medium (WM/F12). The concentrations of latent and active TGF-beta1 in the medium were determined using an immunoassay before and after activation of TGF-beta1 by transient acidification.

RESULTS

The concentration of latent TGF-beta1 in conditioned media from HTF seeded at high density (150 cells/mm2) significantly increased after stimulation with 5 ng/ml TGF-beta1 (151.5 +/-41.7 pg/ml) or 10 ng/ml IL-1beta (45.7+/-8.1 pg/ml). The concentration of active TGF-beta1 in conditioned media also significantly increased after stimulation of HTF with 5 ng/ml TGF-beta1 (48.4+/-27.5 pg/ml).

CONCLUSIONS

The present results indicate that TGF-beta1 is the most potent inducer of its own synthesis in HTF. Activation of an autocrine TGF-beta1 loop may play a role in the wound healing response after glaucoma filtering surgery.