Action of cortisone on tissue reactions of inflammation and repair with special reference to the eye

Modeling Inflammation in Zebrafish for the Development of Anti-inflammatory Drugs

Dysregulation of the inflammatory response in humans can lead to various inflammatory diseases, like asthma and rheumatoid arthritis. The innate branch of the immune system, including macrophage and neutrophil functions, plays a critical role in all inflammatory diseases. This part of the immune system is well-conserved between humans and the zebrafish, which has emerged as a powerful animal model for inflammation, because it offers the possibility to image and study inflammatory responses in vivo at the early life stages. This review focuses on different inflammation models established in zebrafish, and how they are being used for the development of novel anti-inflammatory drugs. The most commonly used model is the tail fin amputation model, in which part of the tail fin of a zebrafish larva is clipped. This model has been used to study fundamental aspects of the inflammatory response, like the role of specific signaling pathways, the migration of leukocytes, and the interaction between different immune cells, and has also been used to screen libraries of natural compounds, approved drugs, and well-characterized pathway inhibitors. In other models the inflammation is induced by chemical treatment, such as lipopolysaccharide (LPS), leukotriene B4 (LTB4), and copper, and some chemical-induced models, such as treatment with trinitrobenzene sulfonic acid (TNBS), specifically model inflammation in the gastro-intestinal tract. Two mutant zebrafish lines, carrying a mutation in the hepatocyte growth factor activator inhibitor 1a gene (hai1a) and the cdp-diacylglycerolinositol 3-phosphatidyltransferase (cdipt) gene, show an inflammatory phenotype, and they provide interesting model systems for studying inflammation. These zebrafish inflammation models are often used to study the anti-inflammatory effects of glucocorticoids, to increase our understanding of the mechanism of action of this class of drugs and to develop novel glucocorticoid drugs. In this review, an overview is provided of the available inflammation models in zebrafish, and how they are used to unravel molecular mechanisms underlying the inflammatory response and to screen for novel anti-inflammatory drugs.

Management of the hyper-filtrating ischaemic bleb: crosslinking with riboflavin and UV radiation versus a conjunctival sliding flap and conjunctival autologous graft

INTRODUCTION

This article compares and evaluates the safety and clinical results of 3techniques for the management of hyper-filtrating ischaemic bleb in glaucoma, such as collagen crosslinking (CXL) with riboflavin versus conjunctival sliding and conjunctival autologous graft.

METHODS

A total of 24 eyes were selected from 18 patients with ischemic blebs that underwent filtering glaucoma surgery between 2012 and 2017 and subjected them to crosslinking using riboflavin (n=4), conjunctival autologous graft (n=5), and conjunctival sliding (n=15). The results of the intraocular pressure (IOP) prior to the procedure and at 12 months were compared, as well as visual acuity and previous anti-glaucoma medication at 12 months.

RESULTS

The 4eyes that underwent CXL, went from a previous mean IOP of 12.11 ± 3.14 to an IOP of 12.32 ±5.29 at one year (P=.655). Five eyes were treated by conjunctival autologous graft, had a previous mean IOP of 11.65 ± 5.76 and an IOP at one year of 14.68 ± 7.21 (P=.273). Fifteen eyes subjected to conjunctival sliding had a previous IOP of 9.32 ±5.34 and at one year it was 15.16 ± 9.24 (P=.021). There were no adverse effects or complications associated with any of the 3techniques.

CONCLUSIONS

The management of the hyper-filtrating ischaemic bleb is difficult. Surgical procedures are associated with increased IOP and need for medication, while CXL using riboflavin and UV radiation does not seem to have an effect on the revitalisation of the bleb.

Collagen crosslinking in the management of leaking cystic blebs: a prospective study

PURPOSE

To evaluate the effectiveness and safety of collagen crosslinking for leaking cystic blebs.

METHODS

A prospective study was conducted on subjects with cystic bleb leaks without indications for urgent surgical intervention. Collagen crosslinking with riboflavin 0.1 % and ultraviolet A irradiation for 30 min was applied to the cystic bleb surface in five patients. Subjects were followed up for at least 20 weeks (mean: 35.5 ± 11.5 weeks) to monitor the length of time to the cessation of bleb leak, as well as visual acuity, intraocular pressure, and the presence of adverse effects arising from the treatment.

RESULTS

Results showed that a single session of collagen crosslinking was effective in stopping cystic bleb leak. In two of the five subjects, the bleb leak subsided 1 week post-treatment, in one patient after 2 weeks, and in the two more complicated cases, after 4 weeks. This effect was maintained for a mean period of 33.5 ± 10.2 weeks after bleb leak cessation. Treatment was effective even in patients with friable conjunctiva following multiple surgical interventions and severe leak, although a longer period was needed for resolution of the bleb leak. The intraocular pressure and visual acuity were largely stable before and after treatment. No side effects or complications arose from this treatment.

CONCLUSIONS

We recommend a trial of collagen crosslinking on leaking cystic blebs without indications for immediate surgical interventions. It is a relatively easy, non-invasive, pain-free, and potential repeatable procedure for treating leaking cystic blebs, with the aim of strengthening the underlying pathological conjunctiva.

Isolation and cultivation of canine corneal cells for in vitro studies on the anti-inflammatory effects of dexamethasone

OBJECTIVE

This study was conducted to establish a protocol for the isolation and culture of canine corneal cells (i.e. endothelium, keratocytes, and epithelium) to be used for in vitro studies on the effects of dexamethasone in corneal inflammation. ANIMAL MATERIAL: Corneal endothelial cells, epithelial cells and keratocytes from enucleated eyes of dogs (euthanized not related to this study) were isolated and cultured.

PROCEDURE

Canine corneal cells were isolated using a combined enzymatic and mechanical technique and separately taken into culture. The three different cell types were verified by phase contrast microscopy, immunofluorescence, and Western blot using antivimentin and anticytokeratin antibodies. The mRNA for the glucocorticoid receptor (GR) was detected using reverse transcriptase polymerase chain reaction (RT-PCR). To study dexamethasone effects, primary cells were stimulated with lipopolysaccharides (LPS) to induce production of inflammatory mediators, particularly prostaglandin E(2) (PGE(2)). The concentration of PGE(2) in cell culture supernatant was determined utilizing an ELISA assay. Results were compared between control, stimulated as well as stimulated and dexamethasone treated cells.

RESULTS

A protocol for the isolation and culture of canine corneal endothelium, keratocytes, and epithelium was successfully established. Using morphological criteria as well as immunocytochemistry and Western blotting the identity of the cells could be verified. RT-PCR of the primary cells showed mRNA for the GR in all three cell types of the canine cornea. Furthermore, stimulation with LPS led to an increased PGE(2)-production in epithelial cells and fibroblasts, which was significant for epithelial cells. The PGE(2)-concentration was decreased in a dose dependent manner by the addition of dexamethasone.

CONCLUSION

The three major cell types of the canine cornea (i.e. endothelium, keratocytes, and epithelium) can be isolated and cultured in vitro. The mRNA for the GR is shown in all three cell types, its functionality is demonstrated by the dose dependent reduction of PGE(2)-production following dexamethasone treatment.

Effects of anti-inflammatory drugs and preservatives on morphologic characteristics and migration of canine corneal epithelial cells in tissue culture

OBJECTIVE

To determine the effects of commonly used ophthalmic corticosteroids, suprofen, polysulfated glycosaminoglycan and preservatives on morphologic characteristics and migration of canine corneal epithelium grown in cell culture.

ANIMALS STUDIED

Corneal epithelial cells harvested from the corneas of euthanized dogs were propagated in cell culture.

PROCEDURES

Canine corneal epithelium was grown in tissue culture. The cells were treated with different corticosteroids, polysulfated glycosaminoglycan, suprofen or preservatives at different concentrations after a defect was created in the monolayer. Cellular morphologic characteristics and closure of the defect were compared between test drugs and controls.

RESULTS

Morphologically the cells treated with dexamethasone were essentially the same as controls. Prednisolone and hydrocortisone caused rounding and shrinkage of the cells. Both suprofen and polysulfated glycosaminoglycan caused no apparent changes in morphologic characteristics at the lowest concentrations tested, but at higher concentrations there was a concentration-dependent degree of rounding and shrinkage. Benzylkonium chloride and thimerosal caused rounding and shrinkage of all the cells at all concentrations tested. Dexamethasone, hydrocortisone, and suprofen did not inhibit epithelial migration over the defects at the lowest concentrations tested. All other drugs and concentrations inhibited cellular migration.

CONCLUSION

Dexamethasone affected the morphologic characteristics and migration of corneal epithelial cells less than hydrocortisone and prednisolone; therefore, dexamethasone may be the drug of choice when a corticosteroid is indicated and an epithelial defect is present. Suprofen and polysulfated glycosaminoglycan caused a concentration-dependent effect on morphologic characteristics and migration. The preservatives caused severe changes and inhibited migration of the canine corneal epithelial cells at all concentrations and may therefore contribute to poor epithelialization of ulcers treated with preservative-containing drugs.

The role of the immune system in conjunctival wound healing after glaucoma surgery

The immune system has a fundamental role in the development and regulation of ocular healing, which plays an important role in the pathogenesis of most blinding diseases. This review discusses the mechanisms of normal wound healing, describing the animal and fetal wound healing models used to provide further insight into normal wound repair. In particular, conjunctival wound repair after glaucoma filtration surgery will be used to illustrate the contributions that the different components of the immune system make to the healing process. The potential role of macrophages, the possible regulatory effect of lymphocytes, and the important role of growth factors and cytokines in the wound healing reaction are discussed. The significance of the immune system in the pathogenesis of aggressive conjunctival scarring is addressed, particularly assessing the predisposing factors, including drugs, age, and ethnicity. The rationale behind the pharmacological agents currently used to modulate the wound healing response and the effects these drugs have on the function of the immune system are described. Finally, potential new therapeutic approaches to regulating the wound healing response are reported.

Dysfunctional filtering blebs

Guarded filtration surgery, is commonly used to control the intraocular pressure (IOP) in glaucomatous patients. Filtration surgery lowers the IOP by creating a fistula between the inner compartments of the eye and the subconjunctival space (i.e., filtering bleb). There are several options to improve the function of filtering blebs and to prevent their failure. However, improvement of IOP control after guarded filtration procedures is associated with a higher frequency of bleb-related complications. Early (e.g., bleb leak, excessive filtration, flat anterior chamber, filtration failure) and late (e.g., bleb leak, excessive filtration and hypotony, symptomatic blebs, bleb encapsulation, filtration failure, bleb infection) complications associated with filtering procedures should be managed adequately to prevent further problems. Techniques to improve the function of filtering blebs and to treat postoperative complications have progressed over the past decade.

William Stewart Duke-Elder, 22 April 1898 - 27 March 1978

William Stewart Duke-Elder was born in Dundee, 5 miles south of his home, the Manse at Tealing, the second of three sons of the Rev. Neil Stewart Elder, Minister of the United Free Church of Scotland, and his wife Isabella, née Duke, the daughter of the Rev. John Duke, also a Minister of the United Free Church of Scotland at Campsie, Stirlingshire. Stewart’s father—the son of John Elder, a merchant in Thurso, Caithness, and his wife, Anne Sutherland—was a scholarly man. Among the prizes he gained was a book given in the Annual Competition in the Town of Thurso, 1871, for ‘the greatest Proficiency in Highest Greek’. Perhaps with others it may have laid the foundation for Stewart’s own fluent, lucid style of writing. There were no eminent scientific or literary forebears in the family, but he relished the thought of an ancestor hanged for sheep-stealing. The Elders are a sept of the Clan Mackintosh whose Coat of Arms bears the Cat o’ Mountain (the Wild Cat of Caithness) and their motto ‘Touch not the Cat bot (without) glove’. Duke-Elder’s own Arms bear the Caithness cats as supporters, and his motto ‘Concilio et labore’.

Effect of a novel soft steroid on the wound healing of rabbit cornea

The effect of a 'soft' anti-inflammatory corticosteroid on the corneal wound healing was investigated in rabbits. Albino rabbits were treated with soft steroid and dexamethasone after linear perforating corneal incision. Soft drug design is aimed to control and direct the drug activity and in vivo metabolism to nontoxic moieties. These drugs are rapidly deactivated after they reach the general circulation. While having good local activity, they thus possess high therapeutic indexes without systemic side effects. The wound healing process was evaluated qualitatively by histology. Photomicrographs are presented to show that the soft steroid is as or more effective than dexamethasone in minimizing scarring in addition to its advantageous metabolic properties. This soft steroid may be an efficient anti-inflammatory and anti-allergic agent in topical application without the majority of unwanted activities of traditional drugs by deliberately simplifying their disposition.

Argon laser treatment of lipid keratopathy

Sixty-three cases of vascularised lipid keratopathy were treated with the argon laser to occlude feeder vessels which had been identified by fluorescein angiography. There was a reduction in extent in 62% and density in 49%. Visual acuity was improved in 48%. Six patients had keratoplasties shortly after treatment, none of which showed graft rejection. Minor complications included temporary haemorrhage into the cornea and iris atrophy. A more serious problem was severe corneal thinning after resorption of lipid. The patients had to be carefully followed up and maintained on a low dose of topical steroid.

Wound healing in glaucoma filtering surgery

Successful glaucoma filtering surgery is characterized by the passage of aqueous humor from the anterior chamber to the subconjunctival space, which results in the formation of a filtering bleb. Aqueous in the subconjunctival space may then exit by multiple pathways. Bleb failure most often results from fibroblast proliferation and subconjunctival fibrosis. Factors associated with an increased risk of bleb failure include youth, aphakia, active anterior segment neovascularization, inflammation, previously failed glaucoma filtering surgery, and, possibly, race. Several surgical and pharmacologic techniques have recently been introduced to enhance success in eyes with poor surgical prognoses. To elucidate the scientific rationale of these methods, we summarize the process of wound healing after glaucoma filtering surgery and describe postoperative clinical and histopathologic features, factors which may affect success, and specific methods to improve surgical success.

Short- and long-term effects of postoperative corticosteroids on trabeculectomy

All patients with primary open-angle or primary angle-closure glaucoma requiring trabeculectomy between January 1982 and January 1983 were entered into a randomized prospective study to evaluate the effect of postoperative corticosteroids. Twenty-three eyes in Group 1 received a cycloplegic and topical antibiotic. Twenty-nine eyes in Group 2 received the same treatment, with the addition of topical 1% prednisolone acetate. Twenty-three eyes in Group 3 received the same treatment as Group 2, with the addition of systemic prednisone. Success rate was significantly improved with the use of topical corticosteroids. Systemic steroids did not prove to be of any added benefit over topical use alone.

Cysts of Tenon's capsule following filtration surgery

Hypertrophy of Tenon's capsule resembling a cyst and recurrence of increased intraocular pressures occurred shortly after glaucoma filtration surgery in eight patients on whom a variety of surgical techniques had been used. Preoperatively, the patients generally had secondary glaucomas with intraocular pressures exceeding 40 mm Hg. The cysts of Tenon's capsule were uniformly localized to the filtration site and were dome-shaped and hard. They were associated with intraocular pressures near the preoperative levels. Three patients were successfully treated with corticosteroids and massage. The others required surgical intervention to restore adequate filtration. Prompt recognition of a Tenon's capsule cyst and appropriate management can restore function to an otherwise failing filtration bleb.

Treatment of lipid keratopathy with the argon laser

Twenty-two patients with lipid keratopathy were treated with argon laser photocoagulation to the feeder vessels. Two were grafted just over a week after treatment and the corneal discs examined histologically. The remainder of the patients were followed up for a least a year. In 6 cases the visual acuity improved, in 3 deteriorated, and in 10 did not change. The density and extent of the lipid deposition were diminished in 50% of cases. The commonest complications were bleeding into the lipid keratopathy and iris damage. The only serious problem was a disciform type of lipid keratopathy that flared up after treatment. Suggestions are made on improvements in the technique of laser application.

The hamster cheek pouch: an experimental model of corneal vascularization

To gain insight into factors that might be responsible for the normal avascularity of the cornea and for its vascularization in certain pathologic states, an experimental model was designed in which corneal vascularization could be studied under controlled conditions in hamster cheek pouch chambers. Normal corneal tissue, as well as corneas that had been altered in a variety of ways (eg, boiled, autoclaved, freeze-thawed) were implanted into hamster cheek pouch chambers. The fate of the transplanted tissue was observed at regular intervals by direct visualization within the hamster cheek pouch at various magnifications and by light and electron microscopy. This report reviews observations on more than 300 such experiments. Normal and injured corneal autografts, allografts and xenografts and nonviable (autoclaved, boiled or freeze-thawed) corneas commonly became vascularized in the cheek pouch. When this occurred, a similar morphologic sequence of events preceded and accompanied the growth of blood vessels into the cornea. Vascular invasion was generally preceded by the formation of granulation tissue around the cornea. This was followed by a leukocytic, and frequently a fibroblastic, infiltration of the cornea. When cells did not invade the transplanted cornea, the cornea invariably remained avascular. In the present model, a swollen cornea was not a sufficient stimulus for corneal vascularization. The data suggest that under certain circumstances leukocytes may produce one or more factors which stimulate directional vascular growth. The findings are viewed in terms of current concepts on corneal vascularization.

Effect of oxygen on developing retinal vessels with particular reference to the problem of retrolental fibroplasia

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The effect of cortisone on the serum lipids and on the development of experimental cholesterol atherosclerosis in the rabbit

An experiment was performed to determine the effect of cortisone on the serum lipids and on the development of experimental cholesterol atherosclerosis in the rabbit. Litter mate rabbits of the same sex were employed; both sexes were represented in the experiment. The report is based upon four experimental groups comprising (1) 12 rabbits fed cholesterol and treated with cortisone vehicle; (2) 12 rabbits fed cholesterol and treated daily with cortisone; (3) 11 rabbits treated with cortisone; and (4) 7 rabbits that received cortisone vehicle. It was observed that: (1) There was less aortic atherosclerosis in the cholesterol-fed cortisone-treated rabbits as judged by both morphological and chemical means than in the rabbits fed cholesterol without cortisone treatment. (2) Cortisone depressed appreciably the hypercholesterolemia resulting from the feeding of cholesterol to rabbits. (3) Cortisone treatment caused a moderate hypercholesterolemia in normal rabbits. (4) Cortisone caused a moderate increase in serum lipid phosphorus equal to that produced by cholesterol feeding alone. (5) The combination of cholesterol feeding and cortisone did not result in a higher phospholipidemia than either one of these agents alone. (6) Cortisone caused a great increase in serum-neutral fat; it was not apparent whether cholesterol feeding affected the neutral fat lipemia due to cortisone treatment alone. (7) The total cholesterol to lipid phosphorus ratio was about normal in the rabbits that received cortisone only. It was doubled in the animals receiving both cholesterol and cortisone, and it was increased about four times in those that received only cholesterol. The significance of the alterations in the serum lipids induced by cortisone is discussed in relation to the inhibition of the development of aortic atherosclerosis that occurred in the cholesterol-fed rabbits treated with cortisone.

Mechanism of corneal vascularization

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The influence of cortisone on the regeneration of tendon and tracheal epithelium in the rat

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