Fibroblast growth-promoting activity in proliferative vitreoretinopathy: antagonism by acetylsalicylic acid

Effect of Oral Prednisone on the Prevention and Management of Proliferative Vitreoretinopathy After Open-Globe Injury

Purpose: To determine the impact of oral prednisone on the final visual acuity (VA) and prevention of proliferative vitreoretinopathy (PVR) in patients having pars plana vitrectomy (PPV) for globe injuries. Methods: A retrospective chart review was performed of all globe injuries with an initial repair and subsequent PPV between 2009 and 2018. Data included the initial VA, zones of injury, initial closure date, time to secondary intervention (PPV), oral prednisone (1 mg/kg/day) use, the final VA, and enucleation rate. Multivariable regression models were used to assess the impact of oral prednisone use on anatomic and functional outcomes. Results: The mean (±SD) patient age was 46.25 ±18.56 years (range, 13-92); 131 (83.9%) were men. Oral prednisone intake was recorded in 81 patients (52.3%). The prednisone group had significantly more zone 3 involvement (P = .001), worse initial VA (2.28 vs 1.92 logMAR; P = .003), and a greater mean number of surgeries (P = .020) than the no-steroids (control) group but an equivalent final logMAR VA (1.57 vs 1.52; P = .881). The prednisone group had significant VA improvement (P = .025); however, oral prednisone use did not predict the development of PVR (29.23% vs 12.90%; odds ratio [OR], 2.81; 95% CI, 0.89-8.85) or retinal detachment (27.27% vs 29.58%; OR, 0.59; 95% CI, 0.23-1.56). Conclusions: Despite a worse initial clinical presentation, patients who received oral prednisone had significant visual improvement compared with the control group. However, oral prednisone (1 mg/kg/day) use at the time of injury did not decrease the PVR rate.

Design and evaluation of pharmaceutical availability, stability and quality of modified viscosity eye drops with choline salicylate

These studies investigate the possibility of developing and using choline salicylate (CS) in ophthalmic therapy in the form of eye drops with increased viscosity. A 0.5% addition of hydroxypropyl methylcellulose (HPMC) was used as the viscosity increasing agent. The ability of CS to cross a hydrophilic membrane (regenerated cellulose membrane) was assessed by determining a rate constant consistent with zero order kinetics. In studies on a porcine cornea, the ability of CS to penetrate into the structure of the cornea was confirmed by determining the content of CS in the cornea after 5 minutes and 3 hours exposure to eye drops. The quality parameters of eye drops were assessed: pH, viscosity, osmolarity and microbiological purity. Stability tests were also performed on eye drops stored in unit minims packaging and in multi-dose bottle packaging. The following storage conditions were adopted: 40°C/75% RH, 25°C/60% RH, 2-8°C. The sensitivity of CS to light was also confirmed. The UV and HPLC-UV methods were used to assess the CS content, while the HPLC-UV and HPLC-MS/MS methods were used to assess the chromatographic purity.

Choline Salicylate Analysis: Chemical Stability and Degradation Product Identification

Choline salicylate (CS) as a derivative of acetylsalicylic acid is commonly used in different drug forms. In medicine, it is applied topically to inflammation of the oral cavity mucosa and in laryngology. However, this substance in the form of an ionic liquid has not been investigated enough. There are no literature studies on stability tests constituting a stage of pre-formulation research. HPLC (Nucleosil C18, 4.6 × 150 mm, 5 μm; methanol-water-acetic acid 60:40:1, 230 nm or 270 nm) and UV (276 nm) methods for the determination of CS in 2% (g/mL) aqueous solutions were developed. Under stress conditions, CS susceptibility to hydrolytic degradation in aqueous medium, hydrochloric acid, sodium hydroxide, and hydrogen peroxide, and the effect of light on the stability of CS solutions were studied with HPLC analysis. The degradation degree of CS and the purity of the solutions were also tested. Choline salicylate has been qualified as practically stable in neutral and acid media, stable in an alkaline medium, very stable in an oxidizing environment, and photolabile in solution. The HPLC-MS/MS method was used to identify 2,3- and 2,5-dihydroxybenzoic acids as degradation products of CS under the tested conditions.

Safety and feasibility of a novel intravitreal tamponade using a silicone oil/acetyl-salicylic acid suspension for proliferative vitreoretinopathy: first results of the Austrian Clinical Multicenter Study

BACKGROUND

The safety and efficacy of a new surgical method of intravitreal tamponade using silicone oil suspended with aspirin (acetylsalicylic acid) was investigated for the treatment of proliferative vitreoretinopathy.

METHODS

The study was designed as a prospective, randomized, controlled, double-blind multicenter study. A total of 29 patients were included; 15 patients were treated with the silicone oil suspended with aspirin, and 14 patients represented the control group receiving only silicone oil. A standard three-port pars plana vitrectomy was performed in 29 eyes of 29 patients. In cases in which the natural lens was present, simultaneous phacoemulsification was required. The control group received as standard therapy a vitreous tamponade with pure 5000 mPas silicone oil and the treatment group received silicone oil containing 0.2 mg/ml aspirin (AS SiO). At 6 months after surgery, the tamponade was removed from all eyes. The main outcome measure was the incidence of retinal redetachment requiring reoperation. Secondary outcome measures were visual acuity and ophthalmic examination results.

RESULTS

The rate of redetachment, defined as the primary outcome parameter, was the same for both groups. The AS SiO was well tolerated and remained clear during the 6-month study period. Clinical examination revealed no signs of local or systemic adverse effects. The visual acuities were well matched before inclusion in the study and there were no significant differences during the follow-up period and in the final visual outcome between the two groups.

CONCLUSIONS

Aspirin delivery by intravitreal silicone oil in the human eye is safe and also may provide a delivery vehicle for other antiproliferative agents to the posterior pole.

The effects of non-steroidal anti-inflammatory drug application on incisional wound healing in rats

OBJECTIVE

There is evidence that non-steroidal anti-inflammatory drugs (NSAIDs) delay both epithelialisation and angiogenesis in the early phases of wound healing because of an antiproliferative effect. We investigated the influence of diclofenac, a non-selective NSAID, on incisional wound healing.

METHOD

Ten male Wistar rats were given 5 mg diclofenac per kg bodyweight per day; 10 rats were given placebo pellets. After 10 days, unimpaired healing occurred independently of drug treatment both macroscopically and microscopically. Histomorphometry revealed a significant reduction (p = 0.006) in fibroblasts after diclofenac application (median 3 166 cells per mm2) compared with the placebo group (median 3940 cells per mm2). Epidermal thickness was not statistically different between the two groups.

RESULTS

Diclofenac diminished the amount of fibroblasts in connective tissue, reflecting the known antiproliferative effect of NSAIDs on fibroblasts. Clinical healing was not affected.

CONCLUSION

We recommend short-term diclofenac application for post-surgical and post-traumatic patients with wounds who would benefit from its antiphlogistic and analgesic effect. However, if wound healing is disturbed, the negative effect of diclofenac on fibroblasts should be considered. This is particularly relevant for patients with chronic wounds or conditions such as diabetes which can delay wound healing.

Slow release of acetylsalicylic acid by intravitreal silicone oil

PURPOSE

To assess in vitro the potential of silicone oil as a delivery system for acetylsalicylic acid (ASA) and to evaluate in vivo the pharmacokinetic distribution of salicylic acid (SA) in the eye.

METHODS

In an experimental model ASA/silicone oil suspension mixed to a concentration of 1.67 mg/mL was investigated for release rate of ASA and SA. In vivo vitrectomy and intravitreal injection of two different ASA/silicone oil suspensions, both mixed to a concentration of 1.67 mg/mL, was performed on two groups, A and B, of New Zealand white rabbits. Salicylic acid concentrations in ocular tissues, aqueous, vitreous, and blood plasma were evaluated at 6 hours, 24 hours, and 5 days using high performance liquid chromatography.

RESULTS

Salicylic acid was detected in all tissues. The highest levels were obtained in the vitreous: 745.4 microg/mL (A) and 640.0 microg/mL (B) at 6 hours. The retina followed with 332.9 ng/mg (A) and 281.3 ng/mg (B) at 6 hours and 31.6 ng/mg (A) and 48.1 ng/mg (B) at day 5. The maximum blood plasma levels were 5.2 microg/mL.

CONCLUSION

Silicone oil is an efficacious delivery system of ASA in vitro and in vivo. Higher concentrations of SA were found in all ocular tissues and fluids when compared to intravenous administration of maximum doses.

Platelets, aspirin, and cardiovascular disease

Aspirin was first synthesised 100 years ago and its preparation and marketing is generally reckoned to have been the foundation of the pharmaceutical industry. For most of the time since then it has been used for the relief of pain and fever. The modern phase of aspirin use commenced with the reporting in 1974 of a randomised controlled trial in the secondary prevention of death by low-dose aspirin given to patients who had suffered a myocardial infarct. Reports of other trials followed and an overview of the first six trials was presented to the inaugural meeting of the Society for Clinical Trials in Philadelphia in 1980. There have been two further major overviews and the most recent, based on 145 trials, established that low-dose aspirin reduces vascular events by around one third. It has been estimated that, used appropriately, aspirin could prevent 100,000 premature deaths each year worldwide, at a cost of about 250 Pounds ($400) per life saved, and about 80 Pounds ($130) per cardiovascular event prevented. The evidence indicates that it is seriously underused at present. The aspirin story continues and trials are in progress to test other possible uses of aspirin, in vascular dementia, colorectal cancer, and cataract.

Induction of arachidonic acid metabolite release by human fibroblasts in proliferative vitreoretinopathy

Proliferative vitreoretinopathy is a severe ocular disorder characterized by unwanted proliferation of cells and excessive production of fibrous tissue, which leads to the formation of cellular membranes on the surface of the retina and in the vitreous. Proliferative vitreoretinopathy is the most common cause of failure in retinal reattachment surgery, approximately occurring in one out of ten operated eyes. Proliferation of retinal pigment epithelial cells and fibroblasts is a cornerstone in the pathogenesis of proliferative vitreoretinopathy. An in vitro-proliferation assay showed previously that intraocular fluid from patients with proliferative vitreoretinopathy is potently effective in stimulating proliferation of human fibroblasts. Here we show that exposure of human fibroblasts to vitreous fluids from patients with proliferative vitreoretinopathy causes a rapid and sustained increase in arachidonic acid metabolite release as measured by competitive enzyme-immunoassay. The findings implicate prostaglandin E2 as a contributor to enhanced intraocular fibrosis in proliferative vitreoretinopathy. As prostaglandin E2 is a mediator of continuous aqueous-blood retinal barrier breakdown in this severe disease, cycclooxygenase inhibitors such as acetylsalicylic acid, which was successfully used in this study for blocking the effect of intraocular fluid, may be useful agents in targeting the progression of intraocular fibrosis.

Interaction of substance P with epidermal growth factor and fibroblast growth factor in cyclooxygenase-dependent proliferation of human skin fibroblasts

Substance P (SP), fibroblast growth factor (FGF), and epidermal growth factor (EGF) are mitogens for fibroblasts. EGF acts as a progression factor, whereas FGF and SP have competence factor activity. The ability of eicosanoids to regulate proliferation of fibroblasts and the increased production of prostaglandins by fibroblasts in response to the growth factors, led us to investigate the involvement of cyclooxygenase-dependent arachidonic acid metabolites in the mitogenic response of serum-starved human skin fibroblasts to SP, FGF, and EGF. We tested the interaction of a submaximal concentration of SP(10(-9)M) with baFGF(40 micrograms/ml) and EGF(0.01 microgram/ml) both on fibroblast proliferation and release of arachidonic acid metabolites. A combination of SP and EGF synergistically stimulated fibroblast proliferation and prostaglandin E2 release, whereas addition of SP to FGF-containing cultures did not affect cell growth. Inhibition of cyclooxygenase by acetylsalicylic acid augmented the growth response of fibroblasts to all: SP, FGF, and EGF. In the presence of acetylsalicylic acid, SP combined with FGF enhanced fibroblasts proliferation, whereas a combination with EGF inhibited cellular growth with respect to growth induced by EGF alone. Thus, interactions of SP with FGF and EGF differently affected the mitogenic response depending on the formation of arachidonic acid metabolites. The findings indicate that eicosanoids may be important mediators of competence and progression factor activities that may determine the effects of substance P on fibroblast proliferation in a cytokine network.