Decorin and suramin inhibit ocular fibroblast collagen production

Use of Platelet-Rich Plasma Plus Suramin, an Antifibrotic Agent, to Improve Muscle Healing After Injuries

BACKGROUND

The increasing use of platelet-rich plasma (PRP) to treat muscle injuries raises concerns because transforming growth factor-beta (TGF-β) in PRP may promote fibrosis in the injured muscle and thus impair muscle regeneration.

PURPOSE

To investigate whether suramin (a TGF-β inhibitor) can reduce muscle fibrosis to improve healing of the injured muscle after PRP treatment and identify the underlying molecular mechanism.

STUDY DESIGN

Controlled laboratory study.

METHODS

Myoblasts isolated from the gastrocnemius muscle of Sprague Dawley rats were treated with PRP or PRP plus suramin. MTT assays were performed to evaluate cell viability. The expression of fibrosis-associated proteins (such as type I collagen and fibronectin), Smad2, and phosphorylated Smad2 was determined using Western blot analysis and immunofluorescent staining. An anti-TGF-β antibody was employed to verify the role of TGF-β in fibronectin expression. Gastrocnemius muscles were injured through a partial transverse incision and then treated using PRP or PRP plus suramin. Hematoxylin and eosin staining was conducted to evaluate the healing process 7 days after the injury. Immunofluorescent staining was performed to evaluate fibronectin expression. Muscle contractile properties-fast-twitch and tetanic strength-were evaluated through electric stimulation.

RESULTS

PRP plus 25 μg/mL of suramin promoted myoblast proliferation. PRP induced fibronectin expression in myoblasts, but suramin reduced this upregulation. The anti-TGF-β antibody also reduced the upregulation of fibronectin expression in the presence of PRP. The upregulation of phosphorylated Smad2 by PRP was reduced by either the anti-TGF-β antibody or suramin. In the animal study, no significant difference was discovered in muscle healing between the PRP versus PRP plus suramin groups. However, the PRP plus suramin group had reduced fibronectin expression at the injury site. Fast-twitch strength and tetanic strength were significantly higher in the injured muscle treated using PRP or PRP plus suramin.

CONCLUSION

Simultaneous PRP and suramin use reduced fibrosis in the injured muscle and promoted healing without negatively affecting the muscle's contractile properties. The underlying molecular mechanism may be associated with the phosphorylated Smad2 pathway.

CLINICAL RELEVANCE

Simultaneous PRP and suramin use may reduce muscle fibrosis without compromising muscle contractile properties and thus improve muscle healing.

Animal models of scarring control

Filtration surgery has, for the past 50 years been key in the treatment of glaucoma yet a significant issue in the long-term success of such surgery is fibrosis limiting aqueous drainage. Numerous methods have been used to reduce such scarring after filtration surgery and animal models have been important in the development of such techniques. First animal models have been central in understanding molecular and cellular changes occurring in fibrosis and thus which pathways might be valuable therapeutic. Secondly animal models have been critical in determining which of these therapies is likely to be most worthwhile. Having said that animals differ substantially from humans in the anatomy of their aqueous drainage pathways and in the mechanisms of fibrotic change. Rodents and lagomorphs vary more markedly from humans than do primates at an anatomic, biochemical and physiological level, and thus the latter might seem more appropriate as models for antifibrotic techniques. However the welfare implications, and thus ethical issues, in using primates are more concerning than with rodents or rabbits and efforts to refine, reduce and replace living animals in such model systems are crucially important. One problem is that the animal models normally involve healthy eyes, not ones with glaucoma. In veterinary ophthalmology we see large numbers of dogs with glaucoma, many of which have filtration implants placed. Potentially these could be a valuable animal model where benefits of antifibrotic treatment could benefit the animals involved and the research seeking to optimise such treatments.

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.

Adventitial SCA-1+ Progenitor Cell Gene Sequencing Reveals the Mechanisms of Cell Migration in Response to Hyperlipidemia

Adventitial progenitor cells, including SCA-1⁺ and mesenchymal stem cells, are believed to be important in vascular remodeling. It has been shown that SCA-1⁺ progenitor cells are involved in neointimal hyperplasia of vein grafts, but little is known concerning their involvement in hyperlipidemia-induced atherosclerosis. We employed single-cell sequencing technology on primary adventitial mouse SCA-1⁺ cells from wild-type and atherosclerotic-prone (ApoE-deficient) mice and found that a group of genes controlling cell migration and matrix protein degradation was highly altered. Adventitial progenitors from ApoE-deficient mice displayed an augmented migratory potential both in vitro and in vivo. This increased migratory ability was mimicked by lipid loading to SCA-1⁺ cells. Furthermore, we show that lipid loading increased miRNA-29b expression and induced sirtuin-1 and matrix metalloproteinase-9 levels to promote cell migration. These results provide direct evidence that blood cholesterol levels influence vascular progenitor cell function, which could be a potential target cell for treatment of vascular disease.

Suramin, Genistein and Collagen Matrix (DuraGen) for Delayed Adjustment after Strabismus Surgery: Which One is Best?

AIM

To evaluate the efficacy and safety of suramin, genistein and collagen matrix for the prevention of inflammation, the reduction of fibrosis and the delay in adjustment after strabismus surgery on a rabbit model.

METHODS

By using an adjustable suture technique, a recession of the superior rectus muscle (SRM) was made in 36 eyes of 18 rabbits. Three study groups were created using genistein, suramin and collagen matrix (n = 6 per group). Two control groups utilized dimethyl sulphoxide (DMSO) (n = 6) and balanced salt solution (n = 12). The adjustments and measurements were made on days 2, 7, 14. After enucleation was done on day 21, the degree of inflammation was evaluated quantitatively in histopathological sections and immunohistochemical investigations were performed for tissue expression of cytoplasmic vascular endothelial growth factor (VEGF), MAC 387, TGF-β and bFGF.

RESULTS

The adhesions between conjunctiva and SRM were significantly less in the collagen matrix and suramin groups (p = 0.002) and adhesions between the sclera and SRM were considerably reduced in the genistein and DMSO groups (p = 0.006) on day 7. Force exerted for adjustment was significantly less in the collagen matrix and suramin groups on day 14 (p = 0.006). Expression of b-FGF was significantly lower in the conjunctival epithelium in the suramin and genistein groups (p = 0.0001 for both). TGF-β was significantly lower (p = 0.001) in the suramin group and VEGF expression was totally absent. MAC 387 expression was lower in the genistein and suramin groups (p = 0.0001).

CONCLUSION

Suramin, genistein and collagen matrix successfully reduce adhesions, and facilitate adjustment following recession surgery. Both suramin and genistein effectively suppress growth factor expression, while collagen matrix offers the longest time interval for adjustability after strabismus surgery.

Co-treatment of suberoylanilide hydroxamic acid and mitomycin-C induces the apoptosis of rabbit tenon's capsule fibroblast and improves the outcome of glaucoma filtration surgery

PURPOSE

This study was undertaken to develop a new treatment modality that would be able to minimize fibrosis and provide better outcome with glaucoma filtration surgery (GFS).

METHODS

We examined whether co-treatment with mitomycin-C (MMC) and histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) efficiently induces apoptosis on rabbit Tenon's capsule fibroblasts (TCF) in vitro. We further examined the effect of co-treatment with SAHA and MMC on the alteration of IOP and the bleb survival in rabbits following GFS.

RESULTS

Co-treatment of MMC and SAHA efficiently induces apoptosis in TCFs via the up-regulation of p53 and increased phosphorylation of p53 on serine 15 and 392. Also, co-treatment of SAHA and low-dose MMC decreases IOP, prolongs bleb survival, and induces apoptosis of cells under the bleb area following GFS.

CONCLUSION

This study shows that a co-treatment of SAHA and MMC could improve the outcome of GFS.

Changes of collagen type III and decorin in paraurethral connective tissue from women with stress urinary incontinence and prolapse

Thirteen premenopausal women with stress urinary incontinence (SUI), 6 with SUI and prolapse, 9 with prolapse, and 19 without prolapse were enrolled to observe the content change of collagen type III and the expression of decorin mRNA in paraurethral connective tissues. Collagen type III from transvaginal biopsies was assayed by immunohistochemical staining and decorin mRNA was detected by real-time PCR. Premenopausal women with SUI had a significantly decreased level of collagen type III. Decorin mRNA expression was significantly increased in both premenopausal SUI+prolapse group and premenopausal prolapse group reflected by the decrease of DeltaCt value compared to their corresponding controls. The results suggest that a high level of decorin mRNA might be associated with the reduced content of collagen type III, resulting in a less flexible form of extracellular matrix in the connective tissue in SUI and prolapse patients.

Synergistic effects of combined cytotoxic and apoptosis-inducing drugs on Tenon's capsule fibroblasts in vitro and in vivo

BACKGROUND

Highly toxic antimetabolites have gained access to routine clinical use to modulate and reduce the amount of postoperative scarring following glaucomatous filtering procedures. It could be speculated that by combining two different antiproliferative substances with different mechanisms of action total amounts of the substances could be decreased and side effects reduced.

METHODS

Twenty-two substances were tested that had antiproliferative effects by acting cytotoxically, inhibiting growth factors, or inducing apoptosis. With combinations of each two substances, cell culture experiments using 3T3 and human Tenon's capsule fibroblasts were performed evaluating cell toxicity, proliferation and migration, the extent of free radicals, and the amount of apoptosis (TUNEL, electron microscopy). The five most potent combinations were used in an animal experiment with rabbits performing filtering procedures. The extent of episcleral scarring was evaluated by histopathology.

RESULTS

The results of the various assays revealed consistently strong effects in 5 of the 462 combinations. Of these five combinations, two were highly effective in the rabbit model. Substances with strong effects when applied in combination included staurosporine, mitomycin, and CD95L.

CONCLUSIONS

We found synergistic effects in assays that evaluated different aspects of cell function. The amount of scarring in an animal experiment was inhibited to a level comparable with a high single dose of mitomycin. Combination therapy of two antiproliferative acting substances may be a promising concept.

The use of suramin, an antifibrotic agent, to improve muscle recovery after strain injury

BACKGROUND

Muscle strain injuries are extremely common in sports medicine. Muscle healing often is hindered by scar tissue formation after injury.

HYPOTHESIS

Suramin can prevent scar tissue formation and improve muscle healing after injury because of its ability to antagonize transforming growth factor-beta1, a fibrotic cytokine.

STUDY DESIGN

Controlled laboratory study.

MATERIALS AND METHODS

In vitro, muscle-derived fibroblasts (a potential cell source of muscle fibrosis) were incubated with suramin and/or transforming growth factor-beta1; a cell growth curve was obtained. In vivo, mouse gastrocnemius muscles were strain injured. Suramin or sham/control intramuscular injections were performed after injury at various time points. Mice were sacrificed at various time points after injury, and skeletal muscle tissue was evaluated by using histological and physiological tests. Statistical analysis was performed by using analysis of variance and Fisher tests.

RESULTS

Suramin decreased the stimulating effect of transforming growth factor-beta1 on the growth of muscle-derived fibroblasts in vitro. Significantly less fibrous scar formation was observed in suramin-treated muscles than in sham-injected muscles. The fast-twitch and tetanus strength of suramin-treated muscles was also significantly greater relative to that of control muscles.

CONCLUSIONS

Suramin blocked the stimulatory effect of transforming growth factor-beta1 on muscle-derived fibroblasts in vitro. Suramin also reduced fibrous scar formation in muscle and enhanced muscle strength in strain-injured skeletal muscle.

CLINICAL RELEVANCE

These results may facilitate the development of strategies to enhance muscle healing after injury.

Comparative effects of TGF-β1 and TGF-β2 on extracellular matrix production, proliferation, migration, and collagen contraction of human Tenon's capsule fibroblasts in pseudoexfoliation and primary open-angle glaucoma

PURPOSE

To comparatively investigate the effects of TGF-beta(1) and TGF-beta(2) on extracellular matrix production, proliferation, migration, and collagen contraction of cultured human Tenon's capsule fibroblasts derived from patients with pseudoexfoliation (PEX) syndrome, PEX glaucoma, primary open-angle glaucoma (POAG), and cataract.

METHODS

Tenon's capsule fibroblasts obtained from four groups of patients were cultured and stimulated with different concentrations (0.1-10 ng ml(-1)) of TGF-beta(1) or TGF-beta(2) for up to 14 days. Cell proliferation was determined with the WST-1 colorimetric assay, cell migration by using the Transwell assay system, and collagen contraction by computerised analysis of three-dimensional collagen lattices and immunohistochemistry for alpha-smooth muscle actin expression. Expression and synthesis of extracellular matrix components (fibronectin, collagen types I and III) was assessed by enzyme-linked immunosorbent assays, by real-time RT-PCR, and by transmission electron microscopy.

RESULTS

Both TGF-beta(1) and TGF-beta(2) in pathophysiological concentrations of 0.1-5 ng ml(-1) stimulated cell proliferation, migration, collagen contraction, alpha-smooth muscle actin expression as well as mRNA expression and secretion of fibronectin, collagen type I, and collagen type III by Tenon's fibroblasts derived from all groups of patients. TGF-beta stimulation occurred in a concentration-dependent manner with different peak activities associated with different fibroblast functions. There was some variability among the different groups of patients with an increased response of cells derived from PEX and POAG patients as compared to cataract patients. Although no statistically significant differences were found between both TGF-beta isoforms, TGF-beta(1) had a more pronounced stimulatory effect on expression and synthesis of extracellular matrix components including the production of elastic microfibrils, particularly in cells derived from patients with PEX syndrome/glaucoma.

CONCLUSIONS

These findings suggest a significant contribution of TGF-beta(1) in addition to TGF-beta(2) to the conjunctival scarring process following glaucoma filtration surgery. Due to its pronounced fibrogenic potential, TGF-beta(1) may become another focus for targeting drug therapy, particularly in patients with PEX glaucoma.

Antifibrotic effects of suramin in injured skeletal muscle after laceration

Muscle injuries are very common in traumatology and sports medicine. Although muscle tissue can regenerate postinjury, the healing process is slow and often incomplete; complete recovery after skeletal muscle injury is hindered by fibrosis. Our studies have shown that decreased fibrosis could improve muscle healing. Suramin has been found to inhibit transforming growth factor (TGF)-beta1 expression by competitively binding to the growth factor receptor. We conducted a series of tests to determine the antifibrotic effects of suramin on muscle laceration injuries. Our results demonstrate that suramin (50 microg/ml) can effectively decrease fibroblast proliferation and fibrotic-protein expression (alpha-smooth muscle actin) in vitro. In vivo, direct injection of suramin (2.5 mg) into injured murine muscle resulted in effective inhibition of muscle fibrosis and enhanced muscle regeneration, which led to efficient functional muscle recovery. These results support our hypothesis that prevention of fibrosis could enhance muscle regeneration, thereby facilitating more efficient muscle healing. This study could significantly contribute to the development of strategies to promote efficient muscle healing and functional recovery.

Effects of age on morphology, protein synthesis and secretagogue-evoked secretory responses in the rat lacrimal gland

This study investigated changes in the morphology and protein synthesis and protein and peroxidase secretion due to peptidergic and aminergic stimulation from rat lacrimal gland acinar cells of 3-5, 9, 12, 20 and 24 month old rats. There was a marked reduction in the presence of Golgi apparatus in the acinar cells of glands from the 24 month old rats coupled to dilatation and degeneration of rough endoplasmic reticulum, when compared to that in the acinar cells of glands from 3-5 and 12 month old rats. Following incorporation of tritiated leucine for 360 min (6 h), the amount of newly synthesised protein in acinar cells of the 12 month old rats was significantly (p < 0.01) higher than that in the acinar cells of 3-5 month old animals. However, at 20 months the amount of newly synthesised protein in these acinar cells was significantly (p < 0.01) reduced to less than that in acinar cells of both the 3-5 and 12 month old animals. Immunohistochemical and immunofluorescence studies identified the presence of substance P (SP), vasoactive intestinal peptide (VIP), histamine and 5-hydroxytryptamine (5-HT) in the lacrimal glands of 3-5 month old rats. Stimulation by either SP, VIP, histamine or 5-HT resulted in significant increases in total protein output and peroxidase release from acinar cells of the 3-5 month old rats. However, all responses to the secretagogues were reduced with ageing from 3-5 to 24 months of age. The results indicate that ageing is associated with alteration in the ability of acinar cells to synthesise and secrete proteins.

A murine cell culture model for post-trabeculectomy anfibrotic treatment: Induction of apoptosis by Cyclosporin

PURPOSE

Experimental trials aimed at the research of selective antifibrotic agents are under development for the alternative treatment of glaucoma patients who are usually considered high-risk post-surgical individuals after trabeculectomy. Authors present here an in vitro model system for the treatment of post-trabeculectomy patients. The study is aimed at the evaluation of different drugs in a mouse fibroblast model.

METHODS

The antifibrotic activity of Cyclosporin A, Interferon 2alpha, 5-Fluorouracyl was investigated on 3T6 cells in culture. Cell viability and proliferation was assessed after drug treatment. Molecular analysis of DNA degradation was evaluated by means of radioactive labeling and gel electrophoresis.

RESULTS

The three drugs were shown to affect cell proliferation and viability in a differential fashion. However, only Cyclosporin A was able to control cell proliferation, inducing apoptosis. This phenomenon was reduced by supplementation of trolox, a compound known to inhibit programmed cell death. These results strongly suggest that this model system might be useful as a test of pharmacological functionality.

CONCLUSION

A rapid and efficient model system is described for the assessment of cell viability and proliferation after treatment with agents of potential pharmacological use. Cyclosporin A induces a significant apoptosis. This is important for the negative control of fibrotic degeneration in post-trabeculectomy that is required for successful surgery in glaucoma patients. Therefore, Cyclosporin A might become a clinically interesting drug for the antifibrotic treatment of post-trabeculectomy.

Suramin inhibits proliferation of human arterial smooth muscle cells in vitro: potential drug for prevention of restenosis by local drug delivery

PURPOSE

Suramin is known to inhibit proliferation of various tumor cells. This study was performed to investigate the effect of suramin on proliferating human arterial smooth muscle cells (HASMC) and thus to examine its suitability for the prevention of restenosis.

METHOD

Proliferation of HASMC was stimulated with human whole blood serum (HWBS), as well as with platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF). Proliferation was assessed by measuring DNA synthesis and cell viability was assessed by measuring mitochondrial activity.

RESULTS

Suramin exerted a strong attenuating effect on the proliferation stimulators HWBS, PDGF, and bFGF. A suramin concentration of 0.5 mmol/L, which is approximately twice the dosage used for systemic application, was sufficient for complete neutralization of proliferation stimulation by 10% HWBS added to the cell culture medium.

CONCLUSION

The authors' data demonstrate a strong proliferation inhibiting effect of suramin on HASMC in vitro. Because it is known to interact not only with one but with a multitude of relevant growth factors, these results make suramin a most interesting substance for local application for prevention of hyperplastic neointima formation.

Glaucoma surgery: are there new perspectives in perioperative pharmacology?

The literature directed at perioperative pharmacologic advances in relation to glaucoma filtration surgery is reviewed. The successful use of subconjunctival anesthesia demonstrates a new alternative in preoperative glaucoma surgical anesthesia. The intraoperative use of the antimetabolites mitomycin C and 5-fluorouracil in both traditional filtration and glaucoma drainage implantation surgery has been expanded. The use of the antifibrinolytic agents urokinase and recombinant tissue plasminogen activator adds a new and controversial dimension to postoperative pharmacologic therapy.